Springer 2006 Familial Cancer (2006) 5:135–142 DOI 10.1007/s10689-005-2832-5 BRCA1 and BRCA2: chemosensitivity, treatment outcomes and prognosis William D. Foulkes Program in Cancer Genetics, Departments of Oncology and Human Genetics, McGill University, Montreal, Quebec, Canada, H2W 1S6 Received 27 August 2004; accepted in revised form 9 February 2005 Key words: chemotherapy, hereditary breast and ovarian cancer, oncology, survival Abstract BRCA1 and BRCA2 are important breast and ovarian cancer susceptibility genes, and mutations in these two genes confer lifetime risks of breast cancer of up to 80% and ovarian cancer risks of up to 40%. Clinico-pathological studies have identiﬁed features that are speciﬁc to BRCA1-related breast cancer, but this has been more diﬃcult for BRCA2-related breast cancer. Ovarian cancers due to BRCA1 or BRCA2 mutations cannot usually be distinguished from their non-hereditary counterparts on morphological grounds, but micro-array data suggest that diﬀerences do exist. Prognostic studies have shown that breast cancer in a BRCA1 mutation carrier is likely to have a similar, or worse, outcome than that occurring in a BRCA2- or non-carrier of the same age. By contrast, most studies indicate that women developing a BRCA1/2-related ovarian cancer have an improved survival compared with non-carriers, particularly if they receive platinum-based therapy. In support of this, in vitro chemo-sensitivity studies have found that human cells lacking BRCA1 may be particularly sensitive to cisplatinum and to other drugs that cause doublestrand breaks in DNA. Nevertheless, in breast cancer, little is known regarding clinically important diﬀerences in response to chemotherapy between BRCA1/2 mutation carriers and non-carriers, and between diﬀerent chemotherapeutic regimens within existing series of BRCA1/2 mutation carriers. There are no published prospective studies. It is hoped that, in the near future, randomised controlled trials will be started with the aim of answering these important clinical questions. Introduction BRCA1 and BRCA2 are important breast cancer and ovarian susceptibility genes, accounting for 2–4% of all breast cancer and 5–10% of ovarian cancer worldwide. A considerably higher percentage of mutation carriers are found in some populations, particularly those where religious, cultural or geographical factors may have limited the ﬂow of genes [1]. Identifying mutations in these genes in women who are at risk of breast/ovarian cancer, or who already developed a cancer, is now part of routine clinical cancer genetics. Indeed, in the Canadian province of Ontario, a large part of the practice of medical genetics is now devoted to breast and ovarian cancer risk assessment [2], and most cancer centres have units devoted to hereditary cancer and/or cancer risk assessment. The purpose of this brief and selective review is to highlight research into the effect of the presence or absence of BRCA1 and BRCA2 mutations on (a) the sensitivity in vitro to certain chemotherapeutic drugs; and (b) the response to chemotherapy in patients with breast or ovarian cancer. Clinical response to radiotherapy or hormonal therapy will not be discussed. I hope to show how the presence of BRCA1/2 mutations may come to inﬂuence the practice of oncology, speciﬁcally the choice of chemotherapeutic agents. Most oncologists do not use mutation status to guide therapy, although there are early suggestions that this information can be useful, particularly if the decision whether or not to give chemotherapy is a diﬃcult one (i.e. on the basis of tumour size and nodal status alone) [3]. Increasingly it is accepted that events early in the life of a breast cancer can determine the long-term outcome [4–6] and that BRCA1-related breast cancers have a speciﬁc gene expression proﬁle that can distinguish such cancers from both BRCA2-related and non-hereditary cancers [5, 7]. Additionally, gene expression proﬁles may Correspondence to: William D. Foulkes ; Fax: +514-9348273; E-mail: [email protected] 136 determine response to certain chemotherapeutic agents [8]. Therefore, it seems plausible that BRCA1 and BRCA2-related breast cancers may possess gene expression proﬁles that will render these tumours particularly susceptible to one type of chemotherapeutic regimen, whereas they may be resistant to another. This is not perhaps very diﬀerent from the situation in nonBRCA1/2-related breast cancer, where similar analyses will soon be possible, but the diﬀerence with hereditary breast cancer is that the pre-existing inherited mutation may favour a speciﬁc initial molecular eﬀect (for example, impaired double-strand DNA repair) or pathological pathway (expression of basal, rather than luminal keratins) which is unlikely to be present in a large sub-set of non-hereditary cancers. This could result in class-based therapy, which may be more ﬁnancially and logistically practical than the much-discussed ‘individualized chemotherapy’. Clinicopathological features of BRCA1/2-related breast cancers The purpose of this section is to illustrate the key differences between three types of breast cancer: BRCA1-related, BRCA2-related and non-hereditary. This will serve as an introduction to the sections on the in vitro and in vivo data that relate speciﬁcally to response to chemotherapeutic agents. Diﬀerences in responses that are observed are likely to be determined, in part, by diﬀerences in gene expression proﬁles, which are reﬂected in the diﬀerent clinico-pathological features of these three groups of breast cancers. BRCA1-related breast cancers tend to be high-grade [9], lymph node negative [10] tumours that do not express estrogen receptors (ER), HER2 [11] or p27Kip1 [12], but do express p53 [13], cyclin E [14] and cytokeratin (CK) 5/6 [15, 16]. A marker of tumour vascularity known as glomeruloid microvascular proliferation (GMP), a feature of glioblastoma multiforme, is signiﬁcantly more likely to be present in BRCA1-related cancers than in other types of breast cancer [17]. In addition, MYC ampliﬁcation appears to be much more frequent in BRCA1-related breast cancer than in nonhereditary breast cancer [18, 19], and this knowledge, when combined with TBX2 status, could possibly used to predict the presence of a BRCA1 mutation [19]. Many of the features of BRCA1-related cancer discussed above are shared with breast cancers that have a basal epithelial phenotype [20, 21] but the true signiﬁcance of this phenotype is not yet known, although most studies have shown that the basal phenotype is associated with an inferior outcome [14, 22–24]. Whether or not this phenotype can be used to determine what type of chemotherapeutic regimen should be employed is an intriguing but unanswered question. The situation for BRCA2 is more complicated: six years ago, the Breast Cancer Linkage Consortium published an analysis of a large number of BRCA2- W. D. Foulkes related breast cancers and showed that, compared with controls, these cancers had (1) a higher score for tubule formation (fewer tubules) (P = 0.0002), (2) a higher proportion of the tumour perimeter with a continuous pushing margin (P = 0.0001), and (3) a lower mitotic count (P = 0.003) [25]. More recent immunohistochemical analyses by the same group showed that is diﬃcult to distinguish BRCA2-related from non-hereditary breast cancer using ER, PR, p53 or erbB-2/HER2 [9], and an analysis of relationship between tumour size and the number of positive axillary lymph nodes also indicates that BRCA2-related breast cancers are more like non-hereditary cancers than are BRCA1-related tumours [10]. Cyclin D1 is more likely to be expressed in BRCA2-related breast cancer (and in sporadic breast cancer) than in BRCA1-related breast cancer [7, 26], and this could be a helpful marker in situations where distinguishing which gene is involved is important. A recent phylogenetic re-analysis of previously published expression array data [7] demonstrated that a distinct branch on the classiﬁcation tree was occupied by BRCA2-positive cancers: this was quite distinct from the BRCA1-related cancer branch. Interestingly, socalled sporadic cancers appeared to be widely spread, and were relatively distant from the path between the BRCA1 and BRCA2 clusters [27]. Chemosensitivity: in vitro results (Table 1) Some of the functions of BRCA1 and BRCA2 proteins, such as the role of BRCA1/2 in DNA repair [39] or apoptosis [30, 40] could be directly involved in response to cytotoxic agents. Mouse and human cell lines deﬁcient in BRCA1 or BRCA2 display an increased sensitivity to agents causing double-strand DNA breaks [41, 42]. In breast and ovarian cell lines, over-expression of wild-type BRCA1 enhanced the apoptotic response to a variety of stimuli, including exposure to ionizing radiation and paclitaxel [30], and absence of BRCA2 protein renders some cell lines particularly sensitive to these agents as well as cisplatin and camptothecin [33, 43]. Other studies demonstrated this hypersensitivity for mitoxantrone, amsacrine, etoposide, doxorubicin and cisplatin with a subsequent increased level of apoptosis, although results have not been entirely consistent [34–36]. Diﬀerences in drug sensitivity might be explained by diﬀering levels of down-stream eﬀectors such as anti-apoptotic BCL-2 [44] or pro-apoptotic caspases in some hereditary breast cancers. Indeed, more recent studies have suggested that BRCA1 acts as a modulator of chemotherapy-induced apoptosis [29]. As noted previously, there are diﬀerent eﬀects depending on which agents are studied: the presence of BRCA1 induces a 10–1000fold increase in resistance to drugs that introduce DNA double-strand breaks, such as etoposide and bleomycin, whereas increased sensitivity for spindle poisons such as paclitaxel was noted. Very similar results were seen in another study, but in this case, BRCA1 null 137 BRCA1/2, chemotherapy and outcome Table 1. Summary of evidence for diﬀerential chemosensitivity in human breast/ovarian/pancreatic or murine cell lines with deﬁned BRCA1/2 levels Drug Wt BRCA1 over-expressed BRCA1 mutated (loss of function) Paclitaxel/ docetaxel Ref. [28] only) vinorelbine (Ref. [29] only) Increased apoptosis [29–31] Cisplatinum Decreased sensitivity [32, 34] Wt BRCA2 over-expressed BRCA2 mutated (loss of function) Comments Decreased apoptosis [29–32]; No eﬀect [28] Increased sensitivity [33] Similar eﬀects seen in one non-BRCA1/2 mutated ovarian cancer cell line (Ref. 33). In Ref. 28, mouse cells null for p53 that were proﬁcient or deﬁcient for Brca1 were used. Increased sensitivity [28, 32, 34, 35] Increased sensitivity [33] In Ref. 33, similar eﬀects seen in one non- BRCA1/2 mutated ovarian cancer cell line Amsacrine Etoposide (topo II poison) Doxorubicin (topo II poison) Increased sensitivity [36] Increased resistance [32] Increased sensitivity [32] Increased sensitivity [36] Decreased sensitivity [32]; Increased sensitivity [28] Mitoxantrone (topo II poison) Increased resistance [36] Bleomycin Increased resistance [29] Mitomycin c Increased resistance [37] Increased sensitivity [37] 5FU, anti-metabolites No change [28] Topotecan/ Camptothecin (topo I poison) Increased sensitivity [28] Busulfan Increased sensitivity [28] Increased sensitivity [36] Increased sensitivity [38] NB checkpoint activation/apoptotic mechanisms were unaﬀected [38] Increased sensitivity [33] Blank cells – no data identiﬁed, NB references in parentheses. cells (HCC1937) were also insensitive to doxorubicin, and this eﬀect was reversed when wild-type BRCA1 was expressed [32]. There are two inferences from these studies: (1) absence of BRCA1 results in an inverse of the chemoresponsive phenotype seen when BRCA1 is present; (2) More controversially, unlike the clinical situation for most breast cancers, those occurring in BRCA1 carriers are more likely to be resistant to paclitaxel than to cisplatinum or etoposide. However, in vitro and in vivo responses to chemotherapy may not be closely correlated. To confuse matters, these results with paclitaxel were contradicted by Zhou et al. who found that the ovarian cancer cell line, SNU-251, that contains a nonsense mutation in BRCA1, had increased cellular sensitivity to ionizing radiation and paclitaxel [31]. This sensitivity was reversed when wild-type BRCA1 was expressed. This cell line is derived from an ovarian, not a breast cancer, as in the previous experiments [29]. It would be instructive to repeat the experiments of Quinn et al. [29] using the same ovarian cancer cell line. To further complicate the picture, when compared with Brca1+/), p53)/) cells, murine embryo ﬁbroblasts lacking both Brca1 and p53 proteins had increased sensitivity to topotecan, doxorubicin, mitoxantrone, etoposide and platinum-containing compounds, but no eﬀect was seen on sensitivity to 5-ﬂuorouracil, gemcitabine, docetaxel or paclitaxel [28]. As shown previously, much of the increased chemosensitivity was revealed by analysis of apoptotic pathways. Again, repeating these experiments using inducible system and human cancer cell lines would be of value, particularly as it known that DNA repair systems, for example, diﬀer between rodents and humans [45]. To emphasize this diﬀerence, increased mRNA levels of BRCA1 predicted a favourable response to anthracycline-containing chemotherapy in 138 W. D. Foulkes a study of 51 patients with breast cancer [46]: the results from the experiments in mice described above would have predicted the reverse eﬀect [28] whereas some previous experiments using the breast cancer line HCC1937 are supportive of these ﬁndings [32]. Interestingly, mRNA levels of p53, erbB-2 and BRCA2 had no eﬀect on response to the cyclophosphamide/ epirubicin regimens used [46]. Methylation of the promotor of BRCA1 could also result in low mRNA levels [47, 48], and it is likely that methylation-based gene silencing could underlie diﬀerences in response to chemotherapy in breast cancer, as has been observed in glioma [49], where a better response to carmustine was observed in individuals with hypermethylation of the O6-methylguanine-DNA methyltransferase promoter than in those without hypermethylation. Interestingly, this hypermethylation is itself a poor prognostic marker, and perhaps a similar poor prognosis/good response combination of eﬀects might exist for mutations that prevent or limit accurate DNA repair, such as BRCA1 or BRCA2, particularly when treatments that cause double-strand breaks in DNA are used. This interpretation is complicated by TP53 data: here certain mutations seem to be both markers of poor prognosis and poor response [50, 51]. On the other hand, the main eﬀect on chemo-responsiveness in cancer cells with TP53 mutations may not operate through the DNA repair pathway, and the complex eﬀects of loss of TP53 on cellular functions may obscure pathwayspeciﬁc diﬀerences. A central role for RAD51 in DNA repair processes has been noted, but the signiﬁcance of the reported association between RAD51 expression levels and resistance to chemotherapy remains uncertain, particularly as studies provide conﬂicting data [52]. Interestingly, several studies have suggested that single nucleotide polymorphisms in RAD51 can modify cancer risk in BRCA2 (but not BRCA1) mutation carriers [53–55]. Forcing cells to repair artiﬁcially created doublestrand breaks by the use of homologous recombination (HR) could lead to cell death in cells that lack intact HR pathways. The premise that BRCA1 and BRCA2 null cells might be especially prone to respond in this fashion was borne out by two recent studies [56,57], that used an inhibitor of the enzyme, poly (ADP-ribose) polymerase (PARP). In these studies, selective inhibitors of PARP1 were tested in mouse and human BRCA1 and BRCA2 null cell lines. BRCA1 or BRCA2 dysfunction profoundly sensitized cells to the inhibition of PARP enzymatic activity. This resulted in chromosomal instability, followed by cell cycle arrest and ﬁnally cell death by apoptosis. This very exciting laboratory work suggests that clinical studies focused on the targeted inhibition of particular DNA repair pathways could be a new and effective way to treat cancers arising in BRCA1 or BRCA2 mutation carriers. Chemosensitivity: in vivo results (Table 2) There have been no prospective randomized controlled trials of different chemotherapeutic regimens in BRCA1/ 2 carriers. The closest to this ideal has been provided by retrospective analysis of completed studies where treatment was not based on mutation status, but was randomly assigned. A differential response to neo-adjuvant chemotherapy for breast cancer on the basis of germ-line BRCA1/2 mutation status may exist. After 3 or 4 cycles of neoadjuvant chemotherapy, a complete clinical response (cCR) was recorded in 10 of 11 BRCA1/2 carriers compared with 8 of 27 non-carriers (P = 0.0009) [58]. Notably, 4 (2 BRCA1 carriers and 2 BRCA2 carriers) of 9 evaluable BRCA1/2 carriers had no residual tumour in the breast and the axillary lymph nodes (a complete pathological response, or pCR), whereas only one case of pCR (4%) was noted among the non-carriers (P = 0.009). When the cases were matched 1:1 to controls on precise TNM stage, the signiﬁcance of the eﬀect of mutation status on complete clinical response rate was slightly less marked. Overall, in this very small retrospective study, BRCA1/2 carriers demonstrated a better clinical response rate to neo-adjuvant chemotherapy than did non-carriers. Importantly, the clinical and pathological responses to adjuvant treatment observed in BRCA1/2 non-carriers were concordant with what has been reported previously, and such responses are not stage-dependent [65]. Support for this observation was provided by a case report from Warner and colleagues [59], who treated a 49-year old woman with neo-adjuvant anthracycline- Table 2. Summary of evidence for diﬀerential response to chemotherapeutic agents in BRCA1- and BRCA2-related breast and ovarian cancers: clinical studies Drug Wt BRCA1 or high levels of wt BRCA1 mRNA BRCA1 mutation or loss of function BRCA2 mutation or loss of function Comments Anthracycline-containing regimens Increased sensitivity [46] Increased sensitivity [58–60] No eﬀect of BRCA2 mRNA levels on response [46] Increased sensitivity [61–64] Increased sensitivity [61–64] Breast cancer studied: small studies, retrospective cohort studies and case reports only Ovarian cancer studied: no diﬀerences between BRCA1 and BRCA2 observed Cisplatinum 139 BRCA1/2, chemotherapy and outcome containing chemotherapy because of a 3 cm invasive ductal breast carcinoma, associated with an ipsilateral 3.5 cm axillary mass. By the middle of the second cycle, no masses could be identiﬁed clinically, by magnetic resonance imaging or by mammography. She was subsequently identiﬁed as a carrier of an Ashkenazi Jewish founder mutation in BRCA1. At deﬁnitive surgery, the total mastectomy specimen was free of cancer. These ﬁndings have been indirectly supported by a recent study that showed that ‘‘basal’’(i.e BRCA1-like) and HER2- positive cancers were the only types of breast cancer which responded well to neo-adjuvant chemotherapy (66). In both groups, 45% had a pCR, exactly the same numbers are seen in the study of Chappuis et al [58], suggesting strongly that the basal pathway is a key factor in the response observed by that group. Another study, also from M.D. Anderson, showed that low levels of BCL-2 are associated with a good response to adjuvant chemotherapy [67], but was not associated with a better long-term survival (BCL-2 positive (56%) vs BCL-2 negative (48%), P = 0.58) Notably, BRCA1-related breast cancers often exhibit low levels of BCL-2 (44). Other basal-associated oncoproteins such a aB-crystallin are also associated with a poor prognosis [68] and the presence of a woundresponse signature, over-represented in basal breast cancers, is also seen in breast cancers that have an adverse outcome [69]. The apparent paradox is that despite this excellent initial response to chemotherapy (as demonstrated by high pCR rates in basal and BRCA1-related breast cancer), cancer is more likely to recur early in basalrelated than in other types of breast cancer (and in our data set, this is true for BRCA1-related cancers too). It appears that although basal breast cancers may respond well to adjuvant chemotherapy [70], response at time of ﬁrst relapse is poor [71], and this could, in part, explain the poor overall prognosis. Well controlled studies of both basal and non-basal forms of BRCA1-related cancer are required to establish the independence of the initial response to chemotherapy in BRCA1 mutation carriers from the basal phenotype. Furthermore, the unsustained nature of the response, in at least some studies, suggests that urgent attempts to identify biological treatments are justiﬁed. The single historical cohort study including a multivariable analysis showed that it is only among affected women not receiving chemotherapy that the presence of a BRCA1 mutation is associated with an adverse prognosis [58]. This provides supporting evidence for a role for BRCA1 in determining response to chemotherapy, but other interpretations of the data are possible, and given then lack of randomization, it is risky to infer too much from such data. The only other study, where the data were not divided by germ-line BRCA1/2 mutation status, but by mRNA levels in the cancers [46], found that, in contrast to the above studies, that increased mRNA levels of BRCA1 predicted a favourable response to anthracycline-containing chemotherapy. As discussed in the previous section, there are conﬂicting data from cell line experiments [28, 32] Several in vitro studies showed increased sensitivity of some ovarian cell lines carrying mutated BRCA1 alleles to various chemotherapeutic agents [30]. Supporting these data, the unbiased historical cohort study by Boyd and colleagues demonstrated that ovarian cancer among Ashkenazi Jewish BRCA1/2 mutation carriers had a better outcome when compared with ovarian cancer in Ashkenazi Jewish non-carriers [61]. Interestingly, although the hereditary and sporadic cancers presented with pathological and treatment (cisplatin-based regimens) characteristics that were remarkably similar, the BRCA1/2-associated cancers were more likely to be optimally cytoreduced at primary surgery and hereditary cases had a signiﬁcantly longer disease-free interval following primary chemotherapy (P = 0.001). These data are compatible with the hypothesis of a more favourable response to chemotherapy among hereditary ovarian cancer cases [61], and have been conﬁrmed by other studies [62–64], although survival diﬀerences between familial and non-familial ovarian cancer (without referring to mutation data) are less apparent [72–74]. There do not appear to be important survival diﬀerences between BRCA1 and BRCA2 mutation carriers. The Fanconi-BRCA ovarian cancer connection The mechanism by which platinum-based drugs produce their effect on ovarian cancer is of substantial interest. It has been observed that Fanconi anemia (FA) cells have increased chromosome breakage and radial formation after cellular exposure to mitomycin C (MMC) [75]. Murine cells lacking Brca1 or Brca2 can also develop a Fanconi anemia-like phenotype, particularly after MMC exposure [37, 38], and FANCD1 has recently been found to be BRCA2 [76]. The BRCA1, BRCA2 and FA gene products interact intimately [77], and normal functioning of this pathway is required for a normal cellular response to DNA cross-linking drugs such as cisplatinum. Recently, it has been suggested that about one-ﬁfth of primary ovarian carcinomas have some disruption of the FANC-BRCA pathway, resulting from biallelic methylation of FANCF [78]. The BRCA1/2 mutation status of the women was not reported. Reversion in one ovarian cancer cell line to cisplatinum resistance was associated with demethylation of FANCF. Therefore cisplatinum sensitivity could, in part, be explained by somatic inactivation of the FANC-BRCA pathway. Hypermethylation of the BRCA1 (and to a lesser extent, BRCA2) promoter is seen in non-hereditary ovarian cancers [48, 79], so it is plausible that the mechanism of cisplatinum sensitivity reported by Taniguchi et al. [78] could have a wider signiﬁcance if methylation of BRCA1 could functionally substitute 140 for methylation of FANCF. Could a similar eﬀect be present in BRCA1/2-related breast cancer? Prognosis in hereditary breast cancer This subject has been extensively reviewed elsewhere and has been alluded to in the sections above. Sufﬁce it to say that most studies ﬁnd that the prognosis for BRCA1-related breast cancer is either similar or worse than age-matched controls. For BRCA2, there are less data, but no substantial diﬀerences in outcome have emerged [3, 80, 81]. Non-BRCA1/2-hereditary breast cancers have a less aggressive proﬁle than BRCA1/2related cancers [82], but the prognostic implication of this has not been studied, for the obvious reason that the genes are not known, and no one single gene or mutation, apart perhaps for CHEK2:1100delC in Finland or the Netherlands, has attained a suﬃcient frequency to permit such an analysis [83]. Surprisingly, other breast cancer susceptibility genes, such as TP53, PTEN and STK11 have not been subjected to survival analyses [81]. Clinical implications and future directions Identifying germ-line BRCA1/2 mutations before deﬁnitive treatment (whether surgical, medical or radiotherapeutic) is beginning to become part of the management of women with breast cancer. Certainly, mutation status inﬂuences surgical choices: women with mutations are much more likely to undergo bilateral mastectomy at primary diagnosis than are non-carriers [84], and this will in turn inﬂuence decisions regarding the use of radiotherapy. As yet, there is only a sense that knowledge of mutation status might inﬂuence the decision to administer chemotherapy to women with small, nodenegative, high-grade breast cancers, insofar as those with BRCA1 mutations may be more likely to beneﬁt than those without [3]. But since many such women probably will receive chemotherapy anyway, this is a marginal contribution. What is more important is if certain regimens are found to be more eﬀective than others in BRCA1/2 carriers. The burning question at the moment is whether platinum-containing compounds will be more eﬀective than taxanes in breast cancer. This conjecture is supported by the literature discussed above. A trial of this nature, in metastatic breast cancer, has just commenced in the U.K. with plans for worldwide enrollment. For anthracyclines, the data are much less clear: most clinical data showing hints of increased responses in BRCA1/2 carriers are based on anthracycline-containing regimens, but the laboratory data are much less encouraging, and the only way to satisfactorily answer these questions will be randomized clinical trials in aﬀected BRCA1/2 mutation carriers. With increasing availability of gene expression data, it may be that clinicians will move straight to the somatic data, without the need to consider germ-line mutation status, and this may obviate the need for such W. D. Foulkes studies in primary breast cancer. Nevertheless, particularly in settings where suitable tissue is not available or hard to access (for example in recurrent disease), knowledge of mutation status could be of value in deciding on the ‘best bet’ for ﬁrst-line chemotherapy. Notably, the BRCA1-associated basal phenotype seen in primary breast cancers appears to be stable over time, and metastases developing months or years later possess a very similar gene expression signature [85], suggesting an important role for BRCA1 in determining the gene expression proﬁles of distant metastases. References 1. Narod SA, Foulkes WD. BRCA1 and BRCA2: 1994 and beyond. Nat Rev Cancer 2004; 4(9): 665–76. 2. Andermann A, Narod SA. Genetic counselling for familial breast and ovarian cancer in Ontario. J Med Genet 2002; 39(9): 695–6. 3. Evans DG, Howell A. Are BRCA1- and BRCA2-related breast cancers associated with increased mortality?. Breast Cancer Res 2004; 6(1): E7. 4. Sorlie T, Perou CM, Tibshirani R et al. Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications. Proc Natl Acad Sci USA 2001; 98(19): 10869–74. 5. Van’t Veer LJ, Dai HY, Vijver MJ et al. Gene expression proﬁling predicts clinical outcome of breast cancer. Nature 2002; 415(6871): 530–6. 6. Sotiriou C, Neo SY, McShane LM et al. Breast cancer classiﬁcation and prognosis based on gene expression proﬁles from a population-based study. Proc Natl Acad Sci USA 2003; 100(18): 10393–8. 7. Hedenfalk I, Duggan D, Chen Y et al. Gene-expression proﬁles in hereditary breast cancer. N Engl J Med 2001; 344(8): 539–48. 8. Sotiriou C, Khanna C, Jazaeri AA et al. Core biopsies can be used to distinguish diﬀerences in expression proﬁling by cDNA microarrays. J Mol Diagn 2002; 4(1): 30–6. 9. Lakhani SR, Vijver MJ, Jacquemier J et al. The pathology of familial breast cancer: predictive value of immunohistochemical markers estrogen receptor, progesterone receptor, HER-2, and p53 in patients with mutations in BRCA1 and BRCA2. J Clin Oncol 2002; 20(9): 2310–8. 10. Foulkes WD, Metcalfe K, Hanna W et al. Disruption of the expected positive correlation between breast tumor size and lymph node status in BRCA1-related breast carcinoma. Cancer 2003; 98(8): 1569–77. 11. Chappuis PO, Nethercot V, Foulkes WD. Clinico-pathological characteristics of BRCA1- and BRCA2-related breast cancer. Semin Surg Oncol 2000; 18: 287–95. 12. Chappuis PO, Kapusta L, Begin LR et al. Germline BRCA1/2 mutations and p27(Kip1) protein levels independently predict outcome after breast cancer. J Clin Oncol 2000; 18(24): 4045–52. 13. Greenblatt MS, Chappuis PO, Bond JP et al. TP53 mutations in breast cancer associated with BRCA1 or BRCA2 germ-line mutations: distinctive spectrum and structural distribution. Cancer Res 2001; 61(10): 4092–7. 14. Foulkes WD, Brunet JS, Stefansson IM et al. The prognostic implication of the basal-like (cyclin E high/p27 low/p53+/glomeruloid-microvascular-proliferation+) phenotype of BRCA1-related breast cancer. Cancer Res 2004; 64(3): 830–5. 15. Sorlie T, Tibshirani R, Parker J et al. Repeated observation of breast tumor subtypes in independent gene expression data sets. Proc Natl Acad Sci USA 2003; 100(14): 8418–23. 16. Foulkes WD, Stefansson IM, Chappuis PO et al. Germline BRCA1 mutations and a basal epithelial phenotype in breast cancer. J Natl Cancer Inst 2003; 95: 1482–5. 141 BRCA1/2, chemotherapy and outcome 17. Goﬃn JR, Straume O, Chappuis PO et al. Glomeruloid microvascular proliferation is associated with p53 expression, germline BRCA1 mutations and an adverse outcome following breast cancer. Br J Cancer 2003; 89(6): 1031–4. 18. Grushko TA, Dignam JJ, Das S et al. MYC is ampliﬁed in BRCA1associated breast cancers. Clin Cancer Res 2004; 10(2): 499–507. 19. Adem C, Soderberg CL, Hafner K et al. ERBB2, TBX2, RPS6KB1, and MYC alterations in breast tissues of BRCA1 and BRCA2 mutation carriers. Genes Chromosomes Cancer 2004; 41(1): 1–11. 20. Korsching E, Packeisen J, Agelopoulos K et al. Cytogenetic alterations and cytokeratin expression patterns in breast cancer: Integrating a new model of breast diﬀerentiation into cytogenetic pathways of breast carcinogenesis. Lab Invest 2002; 82(11): 1525–33. 21. Signoretti S, Di Marcotullio L, Richardson A et al. Oncogenic role of the ubiquitin ligase subunit Skp2 in human breast cancer. J Clin Invest 2002; 110(5): 633–41. 22. Malzahn K, Mitze M, Thoenes M, Moll R. Biological and prognostic signiﬁcance of stratiﬁed epithelial cytokeratins in inﬁltrating ductal breast carcinomas. Virchows Arch Int J Pathol 1998; 433(2): 119–29. 23. Dairkee SH, Mayall BH, Smith HS, Hackett AJ. Monoclonal marker that predicts early recurrence of breast-cancer. Lancet 1987; 1(8531): 514. 24. van de Rijn M, Perou CM, Tibshirani R et al. Expression of cytokeratins 17 and 5 identiﬁes a group of breast carcinomas with poor clinical outcome. Am J Pathol 2002; 161(6): 1991–6. 25. Lakhani SR, Jacquemier J, Sloane JP et al. Multifactorial analysis of diﬀerences between sporadic breast cancers and cancers involving BRCA1 and BRCA2 mutations. J Natl Cancer Inst 1998; 90(15): 1138–45. 26. Vaziri SA, Tubbs RR, Darlington G, Casey G. Absence of CCND1 gene ampliﬁcation in breast tumours of BRCA1 mutation carriers. Mol Pathol 2001; 54(4): 259–63. 27. Desper R, Khan J, Schaﬀer AA. Tumor classiﬁcation using phylogenetic methods on expression data. J Theor Biol 2004; 228(4): 477–96. 28. Fedier A, Steiner RA, Schwarz VA et al. The eﬀect of loss of Brca1 on the sensitivity to anticancer agents in p53-deﬁcient cells. Int J Oncol 2003; 22(5): 1169–73. 29. Quinn JE, Kennedy RD, Mullan PB et al. BRCA1 functions as a diﬀerential modulator of chemotherapy-induced apoptosis. Cancer Res 2003; 63(19): 6221–8. 30. Thangaraju M, Kaufmann SH, Couch FJ. BRCA1 facilitates stress-induced apoptosis in breast and ovarian cancer cell lines. J Biol Chem 2000; 275(43): 33487–96. 31. Zhou C, Smith JL, Liu J. Role of BRCA1 in cellular resistance to paclitaxel and ionizing radiation in an ovarian cancer cell line carrying a defective BRCA1. Oncogene 2003; 22(16): 2396–404. 32. Tassone P, Tagliaferri P, Perricelli A et al. BRCA1 expression modulates chemosensitivity of BRCA1-defective HCC1937 human breast cancer cells. Br J Cancer 2003; 88(8): 1285–91. 33. Samouelian V, Maugard CM, Jolicoeur M et al. Chemosensitivity and radiosensitivity proﬁles of four new human epithelial ovarian cancer cell lines exhibiting genetic alterations in BRCA2, TGFbeta-RII, KRAS2, TP53 and/or CDNK2A. Cancer Chemother Pharmacol 2004. 34. Husain A, He G, Venkatraman ES, Spriggs DR. BRCA1 upregulation is associated with repair-mediated resistance to cis-diamminedichloroplatinum(II). Cancer Res 1998; 58(6): 1120–3. 35. Bhattacharyya A, Ear US, Koller BH et al. The breast cancer susceptibility gene BRCA1 is required for subnuclear assembly of Rad51 and survival following treatment with the DNA crosslinking agent cisplatin. J Biol Chem 2000; 275(31): 23899–903. 36. Abbott DW, Freeman ML, Holt JT. Double-strand break repair deﬁciency and radiation sensitivity in BRCA2 mutant cancer cells. J Natl Cancer Inst 1998; 90(13): 978–85. 37. Moynahan ME, Cui TY, Jasin M. Homology-directed DNA repair, mitomycin-c resistance, and chromosome stability is restored 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. with correction of a Brca1 mutation. Cancer Res 2001; 61(12): 4842–50. Patel KJ, Yu VP, Lee H et al. Involvement of Brca2 in DNA repair. Mol Cell 1998; 1(3): 347–57. Scully R, Livingston DM. In search of the tumour-suppressor functions of BRCA1 and BRCA2. Nature 2000; 408(6811): 429–32. Xu X, Qiao W, Linke SP et al. Genetic interactions between tumor suppressors Brca1 and p53 in apoptosis, cell cycle and tumorigenesis. Nat Genet 2001; 28(3): 266–71. Cortez D, Wang Y, Qin J, Elledge SJ. Requirement of ATMdependent phosphorylation of BRCA1 in the DNA damage response to double-strand breaks. Science 1999; 286(5442): 1162–6. Khanna KK, Jackson SP. DNA double-strand breaks: Signaling, repair and the cancer connection. Nat Genet 2001; 27(3): 247–54. Yuan SSF, Lee SY, Chen G et al. BRCA2 is required for ionizing radiation-induced assembly of rad51 complex in vivo. Cancer Res 1999; 59(15): 3547–51. Freneaux P, Stoppa-Lyonnet D, Mouret E et al. Low expression of bcl-2 in Brca1-associated breast cancers. Br J Cancer 2000; 83(10): 1318–22. Hanawalt PC. Revisiting the rodent repairadox. Environ Mol Mutagen 2001; 38(2–3): 89–96. Egawa C, Motomura K, Miyoshi Y et al. Increased expression of BRCA1 mRNA predicts favorable response to anthracyclinecontaining chemotherapy in breast cancers. Breast Cancer Res Treat 2003; 78(1): 45–50. Catteau A, Harris WH, Xu CF, Solomon E. Methylation of the BRCA1 promoter region in sporadic breast and ovarian cancer: Correlation with disease characteristics. Oncogene 1999; 18(11): 1957–65. Esteller M, Silva JM, Dominguez G et al. Promoter hypermethylation and BRCA1 inactivation in sporadic breast and ovarian tumors. J Natl Cancer Inst 2000; 92(7): 564–9(see comments). Esteller M, Garcia-Foncillas J, Andion E et al. Inactivation of the DNA-repair gene MGMT and the clinical response of gliomas to alkylating agents. N Engl J Med 2000; 343(19): 1350–4. Geisler S, Lonning PE, Aas T et al. Inﬂuence of TP53 gene alterations and c-erbB-2 expression on the response to treatment with doxorubicin in locally advanced breast cancer. Cancer Res 2001; 61(6): 2505–12. Geisler S, Borresen-Dale AL, Johnsen H et al. TP53 gene mutations predict the response to neoadjuvant treatment with 5-ﬂuorouracil and mitomycin in locally advanced breast cancer. Clin Cancer Res 2003; 9(15): 5582–8. Henning W, Sturzbecher HW. Homologous recombination and cell cycle checkpoints: Rad51 in tumour progression and therapy resistance. Toxicology 2003; 193(1–2): 91–109. Levy-Lahad E, Lahad A, Eisenberg S et al. A single nucleotide polymorphism in the RAD51 gene modiﬁes cancer risk in BRCA2 but not BRCA1 carriers. Proc Natl Acad Sci USA 2001; 98(6): 3232–6. Wang WW, Spurdle AB, Kolachana P et al. A single nucleotide polymorphism in the 5¢ untranslated region of RAD51 and risk of cancer among BRCA1/2 mutation carriers. Cancer Epidemiol Biomarkers Prev 2001; 10(9): 955–60. Kadouri L, Kote-Jarai Z, Hubert A et al. A single-nucleotide polymorphism in the RAD51 gene modiﬁes breast cancer risk in BRCA2 carriers, but not in BRCA1 carriers or noncarriers. Br J Cancer 2004; 90(10): 2002–5. Bryant HE, Schultz N, Thomas HD, Parker KM, Flower D, Lopez E, Kyle S, Meuth M, Curtin NJ, Helleday T. Speciﬁc killing of BRCA2-deﬁcient tumours with inhibitors of poly(ADP-ribose) polymerase. Nature. 2005 Apr 14; 434(9035): 913–7. Farmer H, McCabe N, Lord CJ, Tutt AN, Johnson DA, Richardson TB, Santarosa M, Dillon KJ, Hickson I, Knights C, Martin NM, Jackson SP, Smith GC, Ashworth A. Targeting the DNA repair defect in BRCA mutant cells as a therapeutic strategy. Nature. 2005 Apr 14; 434(7035): 917–21. 142 58. Chappuis PO, Goﬃn J, Wong N et al. A signiﬁcant response to neoadjuvant chemotherapy in BRCA1/2 related breast cancer. J Med Genet 2002; 39(8): 608–10. 59. Warner E, Trudeau M, Holloway C. Sensitivity of BRCA-1related breast cancer to neoadjuvant chemotherapy: Practical implications. Breast J 2003; 9(6): 507–8. 60. Robson ME, Chappuis PO, Satagopan J et al. A combined analysis of outcome following breast cancer: Diﬀerences in survival based on BRCA1/BRCA2 mutation status and administration of adjuvant treatment. Breast Cancer Res 2004; 6(1): R8–R17. 61. Boyd J, Sonoda Y, Federici MG et al. Clinicopathologic features of BRCA-linked and sporadic ovarian cancer. JAMA 2000; 283(17): 2260–5. 62. Ramus SJ, Fishman A, Pharoah PD et al. Ovarian cancer survival in Ashkenazi Jewish patients with BRCA1 and BRCA2 mutations. Eur J Surg Oncol 2001; 27(3): 278–81. 63. Ben David Y, Chetrit A, Hirsh-Yechezkel G et al. Eﬀect of BRCA mutations on the length of survival in epithelial ovarian tumors. J Clin Oncol 2002; 20(2): 463–6. 64. Cass I, Baldwin RL, Varkey T et al. Improved survival in women with BRCA-associated ovarian carcinoma. Cancer 2003; 97(9): 2187–95. 65. Wolﬀ AC, Davidson NE. Preoperative therapy in breast cancer: Lessons from the treatment of locally advanced disease. Oncologist 2002; 7(3): 239–45. 66. Rouzier R, Perou CM, Symmans WF, Ibrahim N, Cristofanilli M, Anderson K, Hess KR, Stec J, Ayers M, Wagner P, Morandi P, Fan C, Rabiul I, Ross JS, Hortobagyi GN Pusztai L. Breast cancer molecular subtypes respond diﬀerently to preoperative chemotherapy. Clin Cancer Res. 2005 Aug 15; 11(16): 5678–85. 67. Buchholz TA et al. The nuclear transcription factor kappaB/bc1-2 pathway correlates with pathologic complete response to doxorubicin-based neoadjuvant chemotherapy in human breast cancer. Clin Cancer Res. 2005; 11(23): 8398–8402. 68. Moyano JV et al. AlphaB-crystallin is a novel oncoprotein that predicts poor clinical outcome in breast cancer. J Clin Invest. 2006; 116(1): 261–270. 69. Chang HY et al. Robustness, Scalability, and integration of a wound-response gene expression signature in predicting breast cancer survival. Proc Natl Acad Sci U.S.A. 2005; 102(10): 3738– 3743. 70. Rodriguez-Pinilla SM et al. Prognostic signiﬁcance of basal-like phenotype and fascin expression in node-negative invasive breast carcinomas. Clin Cancer Res. 2006; 12(5): 1533–1539. 71. Banerjee S et al (2006) Basal-like breast carcinomas: clinical outcome and response to chemotherapy. J clin Pathol. W. D. Foulkes 72. Pharoah PD, Easton DF, Stockton DL et al. Survival in familial, BRCA1-associated, and BRCA2-associated epithelial ovarian cancer. United Kingdom Coordinating Committee for Cancer Research (UKCCCR) Familial Ovarian Cancer Study Group. Cancer Res 1999; 59(4): 868–71. 73. Zweemer RP, Verheijen RH, Coebergh JW et al. Survival analysis in familial ovarian cancer, a case control study. Eur J Obstet Gynecol Reprod Biol 2001; 98(2): 219–23. 74. Wojciechowska-Lacka A, Markowska J, Skasko E et al. Frequent disease progression and early recurrence in patients with familial ovarian cancer primarily treated with paclitaxel and cis- or carboplatin (preliminary report). Eur J Gynaecol Oncol 2003; 24(1): 21–4. 75. Tischkowitz MD, Hodgson SV. Fanconi anaemia. J Med Genet 2003; 40(1): 1–10. 76. Howlett NG, Taniguchi T, Olson S et al. Biallelic inactivation of BRCA2 in Fanconi anemia. Science 2002; 297(5581): 606–9. 77. Venkitaraman AR. Tracing the network connecting BRCA and Fanconi anaemia proteins. Nat Rev Cancer 2004; 4(4): 266–76. 78. Taniguchi T, Tischkowitz M, Ameziane N et al. Disruption of the Fanconi anemia-BRCA pathway in cisplatin-sensitive ovarian tumors. Nat Med 2003; 9(5): 568–74. 79. Hilton JL, Geisler JP, Rathe JA et al. Inactivation of BRCA1 and BRCA2 in ovarian cancer. J Natl Cancer Inst 2002; 94(18): 1396– 406. 80. Robson ME, Boyd J, Borgen PI, Cody HS III. Hereditary breast cancer. Curr Probl Surg 2001; 38(6): 387–480. 81. Foulkes WD, Rosenblatt J, Chappuis PO. The contribution of inherited factors to the clinicopathological features and behavior of breast cancer. J Mammary Gland Biol Neoplasia 2001; 6(4): 453–65. 82. Lakhani SR, Gusterson BA, Jacquemier J et al. The pathology of familial breast cancer: Histological features of cancers in families not attributable to mutations in BRCA1 or BRCA2. Clin Cancer Res 2000; 6(3): 782–9. 83. CHEK2*1100delC and susceptibility to breast cancer: A collaborative analysis involving 10,860 breast cancer cases and 9,065 controls from 10 studies. Am J Hum Genet 2004; 74(6): 1175–82. 84. Schwartz MD, Lerman C, Brogan B et al. Impact of BRCA1/ BRCA2 counseling and testing on newly diagnosed breast cancer patients. J Clin Oncol 2004; 22(10): 1823–9. 85. Weigelt B, Hu Z, He X, Livasy C, Carey LA, Ewend MG, Glas AM, Perou CM, Van’t Veer LJ. Molecular portraits and 70-gene prognosis signature are preserved throughout the metastatic process of breast cancer. Cancer Res. 2005; 65(20): 9155–8.