Chemosensitivity and outcome of BRCA1- and BRCA2-associated ovarian cancer patients after first-line chemotherapy compared with sporadic ovarian cancer patients

BackgroundBecause it is insufficiently clear whether BRCA-associated epithelial ovarian cancer (EOC) is more chemosensitive than sporadic EOC, we examined response to chemotherapy, progression-free survival (PFS) and overall survival (OS) in BRCA1- and BRCA2-associated versus sporadic EOC patients.MethodsData about patient characteristics, response to and outcome after primary therapy, including chemotherapy, were collected from 99 BRCA1, 13 BRCA2 and 222 sporadic patients. Analyses were carried out using a chi-square test and Kaplan–Meier and Cox regression methods.ResultsComplete response (CR) or no evidence of disease (NED) was observed in 87% of the BRCA1 patients, progressive disease (PD) in 2%, being 71% and 15%, respectively, in sporadic EOC patients (P = 0.002). In BRCA2 patients, 92% had CR/NED, and none PD (P = 0.27). Median PFS in BRCA1, BRCA2 and sporadic patients was 2.1 [95% confidence interval (CI) 1.9–2.5] years (P = 0.006), 5.6 (95% CI 0.0–11.5) years (P = 0.008) and 1.3 (95% CI 1.1–1.5) years, respectively. Median OS in the three groups was 5.9 (95% CI 4.7–7.0) years (P < 0.001), >10 years (P = 0.008), and 2.9 (95% CI 2.2–3.5) years, respectively. A trend for a longer PFS and OS in BRCA2 compared with BRCA1 patients was observed.ConclusionCompared with sporadic EOC patients, both BRCA1- and BRCA2-associated patients have improved outcomes after primary therapy, including chemotherapy.     

Distant disease-free interval, site of first relapse and post-relapse survival in BRCA1- and BRCA2-associated compared to sporadic breast cancer patients

Background Data on distant disease-free interval (DDFI) and the localization of the first distant metastasis (DM) in BRCA1- and BRCA2-associated breast cancer (BC) patients are as yet scarcely available. Patients and methods We identified 57 BRCA1-associated and 31 BRCA2-associated BC patients, diagnosed between 1980 and 2001, and developing DM disease before 2004, July 1. DDFI, the site(s) of first DM and post-relapse survival of these patients were compared with those of 192 sporadic BC patients. Results As compared to sporadic patients, BRCA1 patients developed less often bone DM (30% vs. 51%; P = 0.005), but tended to develop more often lung DM (26% vs. 16%; P = 0.07), and DM at multiple sites (44% vs. 32%; P = 0.11). In BRCA2-associated compared to sporadic patients, first DM more commonly occurred in lymph nodes (23% vs. 7%; P = 0.007) and at multiple sites (48% vs. 32%; P = 0.08). Adjuvant systemic therapy appeared to be most effective in BRCA2 mutation carriers. Post-relapse survival was worse for BRCA1- and better for BRCA2-associated patients as compared to sporadic patients, but differences disappeared after adjustment for ER-status, site of first DM and DDFI. Conclusion The site of first DM is different between BRCA1- and BRCA2-associated and sporadic BC patients. Differences in post-relapse survival could be explained by differences in site of first DM, in ER-status and in DDFI. Treatment efficacy may differ dependent on genetic status.     

Lympho-vascular invasion in BRCA related breast cancer compared to sporadic controls

Background  

Germline mutations in the BRCA1 gene predispose to the development of breast cancer, exhibiting a specific histological phenotype. Identification of possible hallmarks of these tumors is important for selecting patients for genetic screening and provides inside in carcinogenetic pathways.     

Outcome of triple negative breast cancer: comparison of sporadic and BRCA1-associated cancers

The majority of breast cancers developing in BRCA1 mutation carriers are triple negative breast cancers (TNBC), an aggressive subtype that accounts for 15–20 % of sporadic breast cancer. We compare the clinical outcome and sites of relapse of TNBC in BRCA1 mutation carriers and non-carriers who received adjuvant chemotherapy. Women with stage I–III TNBC who had BRCA1 testing within 36 months of diagnosis and received adjuvant chemotherapy were identified from clinical databases at two academic institutions. Sites of relapse, freedom from distant metastasis (FFDM), and breast cancer-specific survival (BCSS) were determined. RCA1 carriers (n = 89) were significantly younger at diagnosis (P < 0.0001) than non-carriers (n = 175). FFDM at 5 years was 80.5 % for carriers and 76.9 % for non-carriers; with median follow-up of 55 months, hazard ratio (HR) was 0.90, P = 0.71. Sites of recurrence, including brain, did not differ significantly. BCSS at 5 years was 88.1 % for carriers and 81.4 % for non-carriers; HR 0.60; P = 0.15 at 55 months follow-up. BRCA1 carriers who underwent oophorectomy had a significantly lower rate of death from TNBC, with an adjusted HR of 0.30 (95 % CI 0.10–0.94). Adjusting for age, oophorectomy, and prophylactic mastectomy, BRCA1 mutation status was not an independent predictor of survival (HR 2.1; P = 0.13). BRCA1 mutation carriers with TNBC had similar survival rates and sites of recurrence to non-carriers after treatment with conventional chemotherapy. Carriers who underwent oophorectomy had a significantly lower rate of breast cancer-related death; this finding should be studied further in all women with TNBC.     

BRCA1 dysfunction in sporadic basal-like breast cancer

Basal-like breast cancers form a distinct subtype of breast cancer characterized by the expression of markers expressed in normal basal/myoepithelial cells. Breast cancers arising in carriers of germline BRCA1 mutations are predominately of basal-like type, suggesting that BRCA1 dysfunction may play a role in the pathogenesis of sporadic basal-like cancers. We analysed 37 sporadic breast cancers expressing the basal marker cytokeratin 5/6, and age- and grade-matched controls, for downregulation of BRCA1. Although BRCA1 promoter methylation was no more common in basal-like cancers (basal 14% vs controls 11%, P=0.72), BRCA1 messenger RNA expression was twofold lower in basal-like breast cancers compared to matched controls (P=0.008). ID4, a negative regulator of BRCA1, was expressed at 9.1-fold higher levels in basal-like breast cancer (P<0.0001), suggesting a potential mechanism of BRCA1 downregulation. BRCA1 downregulation correlated with the presence of multiple basal markers, revealing heterogeneity in the basal-like phenotype. Finally, we found that 63% of metaplastic breast cancers, a rare type of basal-like cancers, had BRCA1 methylation, in comparison to 12% of controls (P<0.0001). The high prevalence of BRCA1 dysfunction identified in this study could be exploited in the development of novel approaches to targeted treatment of basal-like breast cancer.     

Improved survival for BRCA2-associated serous ovarian cancer compared with both BRCA-negative and BRCA1-associated serous ovarian cancer

BACKGROUND:

Multiple observational studies have suggested that breast cancer gene (BRCA)‐associated ovarian cancers have improved survival compared with BRCA‐negative ovarian cancers. However, most of those studies combined BRCA1 and BRCA2 patients or evaluated only BRCA1 patients. The objective of the current study was to examine whether BRCA1‐associated and BRCA2‐associated ovarian cancers were associated with different outcomes.

METHODS:

This was a single‐institution, retrospective analysis of patients who had a new diagnosis of histologically confirmed stage III or IV serous ovarian, fallopian tube, or primary peritoneal cancer between January 1, 1996 and February 1, 2011 and who underwent BRCA mutation testing on 1 of 2 institutional review board‐approved follow‐up studies. Patients who had been tested for BRCA mutations beyond 24 months of diagnosis were excluded from analysis to minimize selection bias from including patients who were referred for genetic testing because of long survival.

RESULTS:

Data from 190 patients (143 BRCA‐negative patients, 30 BRCA1‐positive patients, and 17 BRCA2‐positive patients) were analyzed. During the study period, 73 deaths were observed (60 BRCA‐negative patients, 10 BRCA1‐positive patients, 3 BRCA2‐positive patients). The median follow‐up for the remaining 117 survivors was 2.5 years. At 3 years, 69.4%, 90.7%, and 100% of BRCA‐negative patients, BRCA1‐positive patients, and BRCA2‐positive patients were alive, respectively. On univariate analysis, age, BRCA2 mutations, debulking status, and type of first‐line therapy (intravenous or intraperitoneal) were significant predictors of overall survival. On multivariate analysis, BRCA2 mutations (hazard ratio, 0.20; 95% confidence interval, 0.06‐0.65; P = .007), but not BRCA1 mutations (hazard ratio, 0.70; 95% confidence interval, 0.36‐1.38; P = .31), predicted for improved overall survival compared with BRCA‐negative patients. When carriers of BRCA2 mutations were directly compared with carriers of BRCA1 mutations, BRCA2 mutations appeared to confer improved overall survival (hazard ratio, 0.29; 95% confidence interval, 0.08‐1.05; P = .060), although this finding did not reach significance.

CONCLUSIONS:

The current data suggests that BRCA2 mutations confer an overall survival advantage compared with either being BRCA‐negative or having a BRCA1 mutation in high‐grade serous ovarian cancer. This finding may have important implications for clinical trial design. Cancer 2012. © 2011 American Cancer Society.     

Tracking evolution of BRCA1-associated breast cancer

Single-cell profiling and computational identification of evolutionary paths to BRCA1-associated tumorigenesis predict that PTEN loss and TP53 mutation precede loss of wild-type BRCA1 in basal-like and luminal tumors, respectively.     

Methylation profiles of the BRCA1 promoter in hereditary and sporadic breast cancer among Han Chinese

The development of breast cancer is a multistep process associated with complex changes in host gene expression patterns including inactivation of tumor suppressor genes and activation of oncogenes. Critically, hereditary predisposition plays a significant role in cancer susceptibility. However, mutation of the BRCA1 gene is found only in the minority of hereditary breast cancer, which indicates that there might be alternative, novel mechanisms contributing to inactivation of the BRCA1 gene. Studies have shown that aberrant methylation of genomic DNA plays an important role in carcinogenesis. The aim of this study was to investigate whether DNA methylation may be an alternative mechanism for the inactivation of BRCA1 as an epigenetic modification of the genome and whether hereditary breast cancer has a different BRCA1 methylation phenotype pattern than sporadic breast cancer. The pattern of CpG island methylation within the promoter region of BRCA1 was assessed by bisulfite sequencing DNA from peripheral blood cells of 72 patients with hereditary predisposition but without BRCA1 mutations and 30 sporadic breast cancer controls. The overall methylation level in patients with hereditary predisposition was significantly lower than that in the sporadic control group. However, patients with hereditary predisposition showed a significantly higher methylation susceptibility for the sites -518 when compared to controls. These results suggest that there might be different BRCA1 promoter methylation levels and patterns in sporadic and hereditary breast cancer in peripheral blood DNA. These findings may facilitate the early diagnosis of hereditary breast cancer.     

Contralateral breast cancer risk is influenced by the age at onset in BRCA1-associated breast cancer

BRCA1/2 mutation carriers diagnosed with breast cancer have a strongly elevated life-time risk of developing a contralateral tumour. We studied the contralateral breast cancer risk in 164 patients from 83 families with a proven BRCA1 mutation in relation to the age at diagnosis of the first primary breast cancer. In the actuarial outcomes after 10 years' follow-up, 40% of the 124 BRCA1-patients diagnosed with breast cancer < 50 years had developed contralateral breast cancer, vs 12% of the 40 patients > 50 years at first diagnosis (Plogrank = 0.02). These data suggest that age at diagnosis of the first tumour should be taken into account when prophylactic mastectomy in BRCA1-patients is considered.     

Methylation of the BRCA1 promoter region in sporadic breast and ovarian cancer: correlation with disease characteristics

Reduced expression of BRCA1 has been reported in sporadic breast cancer, although the mechanisms underlying this phenomenon remain unclear. Abnormal methylation leading to silencing of tumour suppressor genes has been implicated in tumorigenesis in a wide range of sporadic cancers. Therefore, we sought to determine the frequency of methylation within the BRCA1 promoter region in a large group of sporadic invasive breast (n =96) and ovarian (n = 43) carcinomas using Southern analyses. Overall, methylation was detected in 11% of breast cancer cases and in 5% of ovarian tumours. Methylation of the BRCA1 promoter region was strongly correlated with lack of estrogen and progesterone receptor expression. It is clear from the frequency of abnormal methylation of the BRCA1 promoter region, that this cannot be the sole mechanism mediating the reduced expression of BRCA1 that has previously been reported to occur in the majority of invasive sporadic breast tumours. Nevertheless this study suggests that abnormal methylation of the BRCA1 promoter may be important in tumorigenesis in a subset of sporadic breast and ovarian cancers.     

A role for BRCA1 in sporadic breast cancer

To test the hypothesis that altered expression of BRCA1 protein may play an important role in sporadic breast cancer development, 50 randomly selected primary breast cancers (frozen sections, 5 years' median follow-up) were immunolabelled with two monoclonal BRCA1 antibodies (MS110 and MS13). MS110 labelling was exclusively nuclear showing no relation to outcome or tumour pathology. Western blotting demonstrated crossreactivity, suggesting antibody nonspecificity. MS13 labelling was predominantly cytoplasmic. Intense labelling predicted decreased overall survival (P=0.012), disease-free survival (P=0.029), oestrogen receptor negativity (P=0.0004) and c-erbB-2 overexpression (P=0.006). Western blotting detected a 110 kDa molecule consistent with BRCA1 delta11b splice variant. BRCA1 protein is postulated to function as a tumour suppressor. We demonstrate cytoplasmic localisation in sporadic breast cancer suggesting excess delta11b splice variant production, reduced production of full-length BRCA1 and thus postulate reduced tumour suppressor activity. BRCA1 protein appears to have a significant role in both sporadic and hereditary breast cancers.     

MYC is amplified in BRCA1-associated breast cancers.

PURPOSE: Germ-line mutations in the BRCA1 tumor suppressor gene predispose to early onset breast cancers with a distinct phenotype characterized by high tumor grade, aneuploidy, high proliferation rate, and estrogen receptor-negativity. The molecular mechanisms and cooperative oncogenes contributing to multistep tumor progression in cells lacking BRCA1 are not well defined. To examine whether C-MYC (MYC), a transforming oncogene associated with genetic instability, contributes to multistep tumor progression in BRCA1-associated breast cancer, we have analyzed tumors from women with hereditary BRCA1-mutated and sporadic breast cancers. EXPERIMENTAL DESIGN: We performed fluorescence in situ hybridization using a MYC:CEP8 assay on formalin-fixed paraffin-embedded tumor tissues from 40 women with known deleterious germ-line BRCA1 mutations and 62 sporadic cases, including 20 cases with hypermethylation of the BRCA1 gene promoter. RESULTS: We observed a MYC:CEP8 amplification ratio >/=2 in 21 of 40 (53%) BRCA1-mutated tumors compared with 14 of 62 (23%) sporadic tumors (P = 0.003). Of the 14 sporadic cases with MYC amplification, 8 (57%) were BRCA1-methylated. In total, MYC amplification was found in a significantly higher proportion of tumors with BRCA1 dysfunction (29 of 60, 48% versus 6 of 42, 14%; P = 0.0003). In a multivariable regression model controlling for age, tumor size, and estrogen receptor status, BRCA1-mutated tumors demonstrated significantly greater mean MYC:CEP8 ratio than sporadic tumors (P = 0.02). CONCLUSIONS: Our data indicate that MYC oncogene amplification contributes to tumor progression in BRCA1-associated breast cancers. Thus, we conclude that the aggressive histopathological features of BRCA1-associated tumors are in part due to dysregulated MYC activity.     

Preclinical mouse models for BRCA1-associated breast cancer

A substantial part of all hereditary breast cancer cases is caused by BRCA1 germline mutations. In this review, we will discuss the insights into BRCA1 functions that we obtained from mouse models with conventional and conditional mutations in Brca1. The most advanced models closely resemble human BRCA1-related breast cancer and may therefore be useful for addressing clinically relevant questions.     

Familial non-BRCA1/BRCA2-associated breast cancer

Multidisciplinary breast-cancer teams commonly encounter women, both premenopausal and postmenopausal, presenting with breast cancer who also have a family history of this disease. Much of the published work on management of hereditary breast cancer focuses on women with known mutations in BRCA1 and BRCA2, in whom high-grade tumours, common second primaries, and a differential response to adjuvant chemotherapies could be relevant in finding the most effective management strategies. Extrapolation of some of these findings to all patients with familial breast cancer is tempting. However, for women in whom BRCA1 or BRCA2 mutations are unlikely or not found, what evidence is there to inform choices about the various management options? We review the published work on management issues for patients with familial breast cancer not due to a detectable mutation in BRCA1/BRCA2 and compare it with the issues for BRCA1 and BRCA2 carriers on whom more information is available.     

Clinical management of BRCA1- and BRCA2-associated breast cancer

The recent discovery of the breast cancer-associated genes BRCA1 and BRCA2 has changed the clinical care provided to women at high risk of breast cancer. We will review what is currently known about the clinical management of patients who bear (or are suspected of bearing) mutations in either of these two genes. The issues related to establishing a diagnosis of inherited breast cancer, deciding which women are candidates for testing, the limitations of testing, and the predictive power of these tests are addressed. The prognostic features of cancers associated with a BRCA1 and BRCA2 mutation are reviewed. Further, guidelines for prophylaxis of women with a BRCA1 or BRCA2 mutation are given and recommendations are made for the care of mutation carriers with cancer.     

散发性乳腺癌患者BRCA1基因突变分析

目的 :探讨BRCA1基因突变在散发性乳腺癌发生和发展中的作用及在乳腺癌临床诊断和治疗中的应用前景。方法 :应用PCR SSCP和直接测序法检测 3 0例散发性乳腺癌和 15例正常乳腺组织中BR CA1基因外显子 2、11和 2 0的突变情况。结果 :15例正常乳腺组织在 3个外显子上都未显示电泳异常 ,3 0例乳腺癌中有 6例在外显子 2上显示电泳条带异常 ,其中 4例经测序证实有突变 ,1例在外显子 2上 ,3例在内含子拼接区。BRCA1基因突变率在初诊年龄、临床分期和肿瘤体积上差异无统计学意义 ,但与肿瘤转移密切相关。结论 :BRCA1基因突变与散发性乳腺癌的发生和发展密切相关 ,该基因突变筛查可作为一种预后指标。