Dissimilarity between sporadic,non-BRCA1/2 families and hereditary breast cancer,linked to BRCA genes,in the Tunisian population

Background

Most breast cancers (90 %) are sporadic. Only 5–10 % of all cancer cases can be attributed to genetic defects. BRCA genes are strongly incriminated in the hereditary predisposition to the disease. The purpose of our study was to provide more efficient approach to identify pathogenic BRCA mutation carriers and to determine subgroups within the non-BRCA tumor class.

Methods

Different clinicopathological features, reproductive factors, as well as psychosocial ones were compared in women carrying mutations in the BRCA1/BRCA2 genes (12 cases) with non-BRCA1/2 family tumors (36 cases) and age-matched sporadic cases, unselected for family history (44 cases).

Results

A BRCA‐related class was yielded based on age at diagnosis (age ≤ 35 years; p = 0.1), molecular subtypes(the triple-negative subtype was predominant: 43 % of cases; p = 0.025) and age at menarche (p = 0.04). Furthermore, a “probably sporadic” class was distinguished using hormonal contraceptive use (through 30–40 years of age; p = 0.039), the number of full-term pregnancies (age ≥40 years; p = 0.01), age at menopause(age > 50 years; p = 0.04) and psychosocial factors (age ≥ 40 years; p = 0.01). However, analysis of non-BRCA1/2 family tumors indicated that they constitute a heterogeneous class, showing few perceptible differences with sporadic group, but distinct from BRCA1/2 tumors.

Conclusions

In Tunisian population, breast cancer can be classified with a high level of accuracy as sporadic or related to BRCA germline mutations by combining different clinicopathological features and reproductive factors. This can be clinically useful in genetic counseling and decision making for BRCA genetic test.

     

The Retinoblastoma Gene Undergoes Rearrangements in BRCA1-Deficient Basal-like Breast Cancer

Breast tumors from BRCA1 germ line mutation carriers typically exhibit features of the basal-like molecular subtype. However, the specific genes recurrently mutated as a consequence of BRCA1 dysfunction have not been fully elucidated. In this study, we used gene expression profiling to molecularly subtype 577 breast tumors, including 73 breast tumors from BRCA1/2 mutation carriers. Focusing on the RB1 locus, we analyzed 33 BRCA1-mutated, 36 BRCA2-mutated, and 48 non-BRCA1/2-mutated breast tumors using a custom-designed high-density oligomicroarray covering the RB1 gene. We found a strong association between the basal-like subtype and BRCA1-mutated breast tumors and the luminal B subtype and BRCA2-mutated breast tumors. RB1 was identified as a major target for genomic disruption in tumors arising in BRCA1 mutation carriers and in sporadic tumors with BRCA1 promoter methylation but rarely in other breast cancers. Homozygous deletions, intragenic breaks, or microdeletions were found in 33% of BRCA1-mutant tumors, 36% of BRCA1 promoter-methylated basal-like tumors, 13% of non-BRCA1-deficient basal-like tumors, and 3% of BRCA2-mutated tumors. In conclusion, RB1 was frequently inactivated by gross gene disruption in BRCA1 hereditary breast cancer and BRCA1-methylated sporadic basal-like breast cancer but rarely in BRCA2 hereditary breast cancer and non-BRCA1-deficient sporadic breast cancers. Together, our findings show the existence of genetic heterogeneity within the basal-like breast cancer subtype that is based upon BRCA1 status. Cancer Res; 72(16); 4028-36. ?2012 AACR.     

Familial breast cancers without mutations in BRCA1 or BRCA2 have low cyclin E and high cyclin D1 in contrast to cancers in BRCA mutation carriers.

PURPOSE: We analyzed the expression of critical cell cycle regulators cyclin E and cyclin D1 in familial breast cancer, focusing on BRCA mutation-negative tumors. Cyclin E expression in tumors of BRCA1 or BRCA2 carriers is higher, and cyclin D1 expression lower, than in sporadic tumors. In familial non-BRCA1/2 tumors, cyclin E and cyclin D1 expression has not been studied. EXPERIMENTAL DESIGN: Cyclin E and cyclin D1 immunohistochemical expression was studied in tissue microarrays consisting of 53 BRCA1, 58 BRCA2, 798 familial non-BRCA1/2, and 439 sporadic breast tumors. RESULTS: In univariate analysis, BRCA1 tumors had significantly more frequently high cyclin E (88%) and low cyclin D1 (84%) expression than sporadic (54% and 49%, respectively) or familial non-BRCA1/2 (38% and 45%, respectively) tumors. BRCA2 tumors had significantly more frequently low cyclin D1 expression (68%) than sporadic or familial non-BRCA1/2 tumors and significantly more frequently high cyclin E expression than familial non-BRCA1/2 tumors. In a logistic regression model, cyclin expression, early age of onset, and estrogen receptor (ER) and human epidermal growth factor receptor-2 (HER2) status were the independent factors most clearly distinguishing tumors of BRCA1 mutation carriers from other familial breast cancers. High cyclin E and low cyclin D1 expression were also independent predictors of BRCA2 mutation when compared with familial non-BRCA1/2 tumors. Most interestingly, lower frequency of high cyclin E expression independently distinguished familial non-BRCA1/2 tumors also from sporadic ones. CONCLUSIONS: Cyclin E and cyclin D1 expression distinguishes non-BRCA1/2 tumors from both sporadic and BRCA1- and BRCA2-associated tumors and may reflect different predisposition and pathogenesis in these groups.     

Distinct genomic aberration patterns are found in familial breast cancer associated with different immunohistochemical subtypes

Five breast cancer subtypes have been described in sporadic breast cancer (SBC) using expression arrays: basal-like, ERBB2, normal breast-like, luminal A and B. These molecular subtypes show different genomic aberration patterns (GAPs). Recently, our group described these breast cancer subtypes in 50 non-BRCA1/2 familial tumors using immunohistochemistry assays. We extended this study to the other classes of familial breast cancer (FBC), including 62 tumors (18 BRCA1, 16 BRCA2 and 28 non-BRCA1/2), with the same panel of 25 immunohistochemical (IHC) markers and histological grade obtaining a similar classification. We combined these data with results generated by a 1 Mb BAC array-based CGH study to evaluate the genomic aberrations of each group. We found that BRCA1-related tumors are preferentially basal-like, whereas non-BRCA1/2 familial tumors are mainly luminal A subtype. We described distinct GAPs related to each IHC subtype. Basal tumors had a greater number of gains/losses, while luminal B tumors had more high-level DNA amplifications. Our data are similar to those obtained in SBC studies, highlighting the existence of distinct genetic pathways of tumor evolution, common to both SBC and FBC.     

Association of the BRCA1 promoter polymorphism rs11655505 with the risk of familial breast and/or ovarian cancer

Germline mutations in the BRCA1 tumor suppressor gene predispose affected individuals to breast cancer; however, incomplete cancer penetrance and the presence of phenocopies in BRCA1 families also indicate genetic and environmental modifiers of breast cancer risk. In this study, we have tested the single nucleotide polymorphism rs1655505 of the BRCA1 promoter, as candidate for the modifier of breast cancer risk. The polymorphic variants were genotyped in BRCA1-negative (729), familial breast and/or ovarian cancer cases (FBOC), including cases with a reported maternal history (154), nonfamilal (sporadic) cases (600), hereditary breast/ovarian cases with BRCA1 mutations (190) and population controls (1,590) from Central Poland. An association with the risk of FBOC was observed for the minor (T) allele and (TT) genotype (T: p = 0.006, OR = 1.40, 95 % CI = 1.10–1.79; TT: p = 0.001, OR = 2.23, 95 % CI = 1.37–3.62) in female cases with a reported maternal history, specifically in women with the onset of disease after 50 years of age (T: p = 0.004, OR = 1.77, 95 % CI = 1.20–2.62; TT: p = 0.001, OR = 3.7, 95 % CI = 1.62–8.46). The presented evidence suggests a need to conduct larger studies on the association between genetic variations at the BRCA1 promoter and the breast cancer risk, according to maternal/paternal lineage.     

Immunohistochemical expression of DNA repair proteins in familial breast cancer differentiate BRCA2-associated tumors.

PURPOSE: Morphologic and immunohistochemical studies of familial breast cancers have identified specific characteristics associated with BRCA1 mutation-associated tumors when compared with BRCA2 and non-BRCA1/2 tumors, but have not identified differences between BRCA2 and non-BRCA1/2 tumors. Because BRCA1 and BRCA2 genes participate in the DNA repair pathway, we have performed an immunohistochemical study with markers related to this pathway to establish the profile of the three groups. MATERIALS AND METHODS: We have studied two tissue microarrays that include 103 familial and 104 sporadic breast tumors, with a panel of DNA repair markers including ATM, CHEK2, RAD51, RAD50, XRCC3, and proliferating cell nuclear antigen. RESULTS: We found more frequent expression of CHEK2 in BRCA1 and BRCA2 tumors than in non-BRCA1/2 and sporadic tumors. We found absence of nuclear expression and presence of cytoplasmic expression of RAD51 in BRCA2 tumors that differentiate them from other familial tumors. We validated these results with a new series of patient cases. The final study with 253 familial patient cases (74 BRCA1, 71 BRCA2, 108 non-BRCA1/2), and 288 sporadic patient cases, has allowed us to confirm our preliminary results. Because BRCA2 tumors present a specific immunohistochemical profile for RAD51 and CHEK2 markers that is different from non-BRCA1/2 tumors, we have built a multivariate model with these markers that distinguish both tumors with an estimated probability of at least 76%. CONCLUSION: Our results suggest that BRCA2 tumors demonstrate more cytoplasmic and less nuclear RAD51 staining, and increased CHEK2 staining. This pattern may distinguish BRCA2 from familial non-BRCA1/2 tumors.     

Revisiting breast cancer patients who previously tested negative for <Emphasis Type="Italic">BRCA</Emphasis> mutations using a 12-gene panel

Purpose

BRCA mutations contribute to about 20% of all hereditary breast cancers. With full-genome sequencing as the emerging standard for genetic testing, other breast cancer susceptibility genes have been identified and may collectively contribute to up to 30% of all hereditary breast cancers. We re-assessed women who had previously tested negative for a BRCA mutation when outdated techniques were used, and discuss the implications of identifying a mutation several years after initial genetic testing.

Methods

We evaluated the prevalence of mutations in 12 breast cancer susceptibility genes (including BRCA1 and BRCA2) in 190 breast cancer patients with a strong family history of breast cancer. These women had previously tested negative for mutations in the large coding exons of BRCA1 and BRCA2 using the protein truncation test (PTT) between the years of 1996 and 2013.

Results

We identified pathogenic mutations in 17 of 190 (9%) women. Six mutations were detected in BRCA1 (n = 2) and BRCA2 (n = 4). Eleven mutations were found in other breast cancer susceptibility genes including CHEK2 (n = 5), PALB2 (n = 2), BLM (n = 2), ATM (n = 1) and TP53 (n = 1).

Conclusion

Among 190 breast cancer patients with a family history of the disease, and who previously received a negative result for BRCA mutations using the PTT, 17 (9%) women were found to carry a high-risk pathogenic mutation in a breast cancer susceptibility gene. Six of these women were BRCA mutation carriers who were missed previously. These findings support the rationale for updated genetic testing in patients who tested BRCA mutation negative using outdated techniques.

     

Evaluation of established breast cancer risk factors as modifiers of BRCA1 or BRCA2: a multi-center case-only analysis

The incomplete penetrance of mutations in BRCA1 and BRCA2 suggests that some combination of environmental and genetic factors modifies the risk of breast cancer in mutation carriers. This study sought to identify possible interactions between established breast cancer risk factors and BRCA1 or BRCA2 mutations using a case-only study design. Breast cancer cases that had been tested for BRCA1 and BRCA2 mutations were identified from 11 collaborating centers. Comparisons of reproductive and lifestyle risk factors were made between women with breast cancer who were positive for BRCA1 mutations (n = 283), BRCA2 mutations (n = 204), or negative for both BRCA1 and BRCA2 mutations (n = 894). Interaction risk ratios (IRRs) were calculated using multinominal logistic regression models. Compared with non-carriers, statistically significant IRRs were observed for later age at menarche among BRCA2 mutation carriers, for a greater number of pregnancies among both BRCA1 and BRCA2 mutation carriers, and for alcohol use among BRCA1 mutation carriers. Our data suggest that the risk for breast cancer among BRCA1 or BRCA2 carriers may be modified by reproductive characteristics and alcohol use. However, our results should be interpreted cautiously given the overall inconsistency in the epidemiologic literature on modifiers of BRCA1 and BRCA2.     

BRCA1 promoter methylation status does not predict response to tamoxifen in sporadic breast cancer patients

The purpose of this study is to investigate whether BRCA1 promoter methylation is associated with poorer outcome in sporadic breast cancer cases treated with tamoxifen. BRCA1 promoter methylation was determined by bisulfite pyrosequencing in two groups of sporadic breast cancer patients, systemically untreated (N = 497) and treated with adjuvant tamoxifen (N = 497). Associations of BRCA1 promoter methylation with clinopathological characteristics and the effect of BRCA1 promoter methylation on time to first recurrence (TTR) and overall survival (OS) were examined. No significant differences were observed between BRCA1 promoter methylation and clinopathological characteristics in untreated and tamoxifen-treated groups. Cut point analysis did not find any promising cut point for BRCA1 promoter methylation that would differentially influence TTR and OS in untreated and tamoxifen-treated group. Using the median (2.53 %) and an arbitrary value of 10 % as a cut point for methylation, we still found no significant effect of BRCA1 promoter methylation on TTR and OS in untreated and tamoxifen-treated group. Despite data suggesting that BRCA1 levels impact estrogen receptor response to tamoxifen, our results indicate that BRCA1 promoter methylation is not associated with poorer outcome in sporadic breast cancer cases treated with tamoxifen.     

Genetic contribution of GADD45A to susceptibility to sporadic and non-BRCA1/2 familial breast cancers: a systematic evaluation in Chinese populations

Growth arrest and DNA damage-induced 45, alpha (GADD45A) is a candidate breast cancer susceptibility gene because its product participates in DNA repair and it is a downstream gene of p53 and BRCA1, both of which are breast cancer susceptibility genes. We screened germline mutations of GADD45A in 185 non-BRCA1/2 familial breast cancer patients, but no deleterious mutation was found. Seven single-nucleotide-polymorphisms were identified in a subsample. Five common variants (minor allele frequency > 10%) were genotyped for association analyses to scrutinize the relationship between breast cancer and polymorphisms in GADD45A in two independent population sets (total n = 1,861). In the first case–control study (n = 1,457, cases 820, controls 637), a comparison of genotype frequencies between sporadic breast cancer patients and controls indicated the CT/TT-genotypes of +1506C>T and CG/CC-genotypes of +3204G>C were associated with decreased breast cancer risk (adjusted odds ratio (OR), 0.77; 95% confidence interval (CI), 0.62–0.96; and adjusted OR, 0.71; 95%CI, 0.57–0.88, respectively) compared with their wild-type homozygotes. A common haplotype CGTCC was also associated with reduced risk (P = 1.0 × 10^?4). In a second familial breast cancer patient-based case–control study (n = 404, cases 185, controls 219), although +1506C>T and +3204G>C failed to be validated, the haplotype CGTCC showed a borderline significance. Notably, the combined P-values were robust for +3204G>C (P = 3.1 × 10^?4) and CGTCC (P = 1.6 × 10^?5). Moreover, CGTCC was correlated with a higher GADD45A expression in normal breast tissues. In conclusion, although germline mutations of GADD45A is not common in familial breast cancer patients, polymorphisms/haplotypes in GADD45A contribute to breast cancer risk, at least to sporadic breast cancer.     

Local therapy in BRCA1 and BRCA2 mutation carriers with operable breast cancer: comparison of breast conservation and mastectomy

Women with BRCA1 and BRCA2 mutations have an elevated risk of breast cancer and ovarian cancer, but also of developing second primary breast cancer. BRCA1/2 mutation carriers with breast cancer must choose between breast conservation (BCT) and mastectomy (M) yet data on outcomes are limited. The purpose of this study is to compare long-term outcome following BCT and M in BRCA1/2 carriers. 655 women with BRCA1/2 mutations diagnosed with breast cancer and treated with BCT (n = 302) or M (n = 353) were identified and underwent follow-up to assess local, regional, and systemic recurrence. Local failure as first failure was significantly more likely in those treated with BCT compared to M, with a cumulative estimated risk of 23.5 vs. 5.5%, respectively, at 15 years (P < 0.0001); 15-year estimates in carriers treated with BCT and chemotherapy was 11.9% (P = 0.08 when compared to M). Most events appeared to be second primary cancers rather than failure to control the primary tumor. The risk of contralateral breast cancer was high in all groups, exceeding 40%, but was not statistically significantly different by use of adjuvant radiotherapy (RT) or not, suggesting no added risk from scatter RT at 10 and 15 years. There were no differences seen in regional or systemic recurrences between the BCT and M groups, and no difference in overall survival. In conclusion, BRCA1/2 mutation carriers with breast cancer have similar survival whether treated with M or BCT. However, women undergoing BCT have an elevated risk of a second in-breast event that is significantly reduced in the presence of chemotherapy. Contralateral breast cancer events are very common.     

BRCA2 mutations and androgen receptor expression as independent predictors of outcome of male breast cancer patients.

PURPOSE: Germline mutations of the BRCA2 gene are involved in the development of a considerable number of male breast cancer cases. Although phenotypic differences have been observed between sporadic and BRCA-related breast carcinomas, conflicting data exist on the differences in prognosis of women with hereditary and sporadic breast cancer. The purpose of the study was to investigate the prognostic value of BRCA2 status in male breast carcinoma (MBC). EXPERIMENTAL DESIGN: We studied 43 male breast cancer patients, including 12 with BRCA2 mutations. Tumor samples were characterized immunohistochemically using antibodies to estrogen receptor, progesterone receptor, and androgen receptor (AR). RESULTS: BRCA2-related tumors presented at the earlier age compared with sporadic tumors (P = 0.005). Patients positive and negative for BRCA2 mutations did not differ with respect to tumor size, lymph node involvement, histological grade, and sex hormone receptor status. Five-year disease-free survival (DFS) and overall survival (OS) were significantly decreased in BRCA2-positive patients (67% versus 28% for BRCA2-negative versus positive patients, respectively, P = 0.017 for DFS; 86% versus 25%, P = 0.006 for OS). Shorter survival was also correlated with expression of AR in tumor tissue (74% versus 33% for patients with tumors staining negatively and positively for AR, P = 0.029 for DFS; 71% versus 57%, P = 0.05 for OS). CONCLUSIONS: The BRCA2 mutations and AR expression in tumor tissue are independent adverse factors for MBC prognosis. BRCA2-related MBC presents at the earlier age compared with non-BRCA2-related cancer, but do not differ with respect to other clinicopathological features.     

Clinical Contribution of Next-Generation Sequencing Multigene Panel Testing for BRCA Negative High-Risk Patients With Breast Cancer

BackgroundBreast cancer is the most common malignancy in women and thought to be hereditary in 10% of patients. Recent next-generation sequencing studies have increased the detection of pathogenic or likely pathogenic (P/LP) variants in genes other than BRCA1/2 in patients with breast cancer. This study evaluated pathogenic variants, likely pathogenic variants, and variants of unknown significance in 18 hereditary cancer susceptibility genes in patients with BRCA1/2-negative breast cancer.Patients and MethodsThis retrospective study included 188 high-risk BRCA1/2-negative patients with breast cancer tested with a multigene cancer panel using next-generation sequencing.ResultsAmong 188 proband cases, 18 variants in 21 patients (11.1%) were classified as P/LP in PALB2 (n = 6), CHEK2 (n = 5), MUTYH (n = 4), ATM (n = 3), TP53 (n = 2), BRIP1 (n = 1), and MSH2 (n = 1). Three novel P/LP variants were identified. An additional 28 variants were classified as variants of unknown significance and detected in 30 different patients (15.9%).ConclusionThis is one of the largest study from Turkey to investigate the mutation spectrum in non-BRCA hereditary breast cancer susceptibility genes. A multigene panel test increased the likelihood of identifying a molecular diagnosis in patients with BRCA 1/2-negative breast cancer at risk for a hereditary breast cancer syndrome. More studies are needed to enable the clinical interpretation of these P/LP variants in hereditary patients with breast cancer.     

Selection bias influences reported contralateral breast cancer incidence and survival in high risk non-BRCA1/2 patients

Summary Purpose The results of studies comparing survival in familial and sporadic breast cancer (BC) are inconsistent. A higher incidence of contralateral breast cancer (CBC) has been reported in familial BC. Ascertainment bias may influence both the reported familial CBC and survival. Design We assessed CBC incidence, distant disease free (DDFS) and overall survival (OS) in 327 BC patients who had ≥3 breast and/or ovarian cancers in the family but no BRCA1/2 gene mutation (non-BRCA1/2). They were matched to 327 sporadic controls for year and age at detection. To correct for ascertainment bias, we analyzed also separately the results (1) Of the 250 non-BRCA1/2 patients with DNA testing performed before diagnosis or within 2 years (‘unselected’) and (2) Of the 77 with testing ≥2 years after diagnosis (late-tested). Results Median follow-up of non-BRCA1/2 patients was 6.1 yrs. Ten years CBC incidence was 11% in non-BRCA1/2 versus 6% in sporadic patients (p=0.002). At multivariate analysis CBC incidence was increased in late-tested non-BRCA1/2 (HR 4.6; p=0.001) not in ‘unselected’ (HR 1.8; p=0.1). Increased CBC occurred in non-BRCA1/2 patients mainly before genetic testing, suggesting ascertainment bias. Tumors were ≤T1 in 62% of non-BRCA1/2 versus 50% of sporadic patients (p=0.003), node-negative in 55% versus 52% respectively (p=0.5). After correction for stage and therapy, OS did not differ between ‘unselected’ non-BRCA1/2 and sporadic patients (HR 0.8; p=0.3), but was improved in late-tested non-BRCA1/2. Conclusion Overall survival and contralateral breast cancer incidence were similar in ‘unselected’ non-BRCA1/2− and sporadic patients. Reports of higher CBC incidence and better survival in non-BRCA1/2 patients may substantially be caused by DNA testing selection-bias.     

Long-term prognosis of early-onset breast cancer in a population-based cohort with a known BRCA1/2 mutation status

All women in the South Sweden Health Care Region with breast cancer diagnosed aged less than 41 during the period between 1990 and 1995 were contacted in 1996 and offered germline mutation analysis of the BRCA1 and BRCA2 genes. Mutation carriers (n = 20) were compared with noncarriers (n = 201) for overall survival (OS) and risk of contralateral breast cancer (CBC). Mutation carriers were younger at diagnosis and more likely to have ER-negative, PgR-negative and grade III tumors. Median follow-up was 19 years. The 5-, 10-, 15-, and 20-year OS were 60, 45, 39, and 39 % for mutation carriers and 82, 70, 59, and 53 % for noncarriers, respectively (5-year log-rank P = 0.013; 10-year P = 0.008; 15-year P = 0.020; and 20-year P = 0.046). In univariable analysis, there was a trend for an inferior OS for mutation carriers (HR 1.8; 95 % CI 1.0–3.3). When stratified for use of (neo)adjuvant chemotherapy, an inferior OS was significant only for the subgroup of patients who did not receive chemotherapy (HR 3.0; 95 % CI 1.2–7.7). In multivarible analysis, BRCA1/2 mutation status was a significant predictor of OS when adjusting for tumor stage, age, and use of chemotherapy, but not when ER status was also included in the model. The 15-year cumulative risk of CBC was 53 % for mutation carriers and 10 % for noncarriers (HR 5.9; 95 % CI 1.9–18.6); among the noncarriers the risks were 5, 22, and 30 % for patients without close relatives having breast cancer, with second-degree relatives having breast cancer, and with firstdegree relatives with breast cancer, respectively. In conclusion, the poor prognosis of young BRCA1/2 mutation carriers with breast cancer is mainly explained by the prevalent occurrence of negative prognostic factors rather than mutation status per se, and can to at least some extent be abrogated by the use of chemotherapy.     

The pathology of familial breast cancer: histological features of cancers in families not attributable to mutations in BRCA1 or BRCA2.

Breast cancers arising in carriers of mutations in the breast cancer susceptibility genes, BRCA1 and BRCA2, differ histologically from each other and from breast cancers unselected for a family history. However, a substantial proportion of families with multiple cases of breast cancer is not attributable to these two genes (non-BRCA1/2 families). We have now characterized the pathology of 82 breast cancers from non-BRCA1/2 families. Breast cancers in non-BRCA1/2 families were of lower grade (P = 0.0018), showed fewer mitoses (P < 0.0001), less nuclear pleomorphism (P = 0.0014), less lymphocytic infiltrate (P < 0.0001), a lesser extent of the tumor with a continuous pushing margin (P = 0.004), a lesser extent of the tumor composed of solid sheets of cells (P = 0.0047), less necrosis (P = 0.002), and wereparison with BRCA2 tumors, non-BRCA1/2 tumors were lower grade (P = 0.017) and exhibited less pleomorphism (P = 0.01) and more tubule formation (P = 0.05). In comparison with control breast cancers unselected for a family history of the disease, non-BRCA1/2 tumors were of significantly lower grade (P = 0.001), showed less pleomorphism (P = 0.0002), and had a lower mitotic count (P = 0.003). The results indicate that non-BRCA1/2 breast cancers differ histologically from both BRCA1 and BRCA2 breast cancers and are overall of lower grade. They also suggest that non-BRCA1/2 breast cancers differ from nonfamilial breast cancers, but these differences may be attributable to various types of bias.     

BRCA1 promoter methylation is a marker of better response to anthracycline-based therapy in sporadic TNBC

The aim of the current study was to investigate the role of BRCA1 gene aberrations in sporadic triple-negative breast cancer (TNBC) and its impact on anthracycline-based therapy. BRCA1 promoter methylation was analyzed in 70 TNBC and compared with the clinical and pathologic characteristics. As a control group, we used 70 patients with non-TNBC. BRCA1 promoter methylation was observed in 65.2 % of patients and was similar in both groups. BRCA1 promoter methylation was associated with decreased intensity of BRCA1 protein expression (P = 0.002) and significant increase of median disease-free survival (DFS) of TNBC patients receiving adjuvant anthracycline-based chemotherapy (P = 0.001). Multivariate analysis revealed that BRCA1 promoter methylation remains a favorable factor in regard to DFS (HR 0.224; 95 % CI 0.092–0.546, P = 0.001) in TNBC after adjustment for other prognostic factors. In contrast, in non-TNBC, BRCA1 promoter methylation was not associated with any clinical and pathologic parameters. BRCA1 promoter methylation is a common mechanism of BRCA1 gene aberration in sporadic breast cancer and is predictive for better response to anthracycline-based therapies.     

Differing effects of adjuvant chemotherapy according to BRCA1 nuclear expression in gastric cancer

Background

We aimed to investigate the role of BRCA1 nuclear expression in sporadic gastric cancer; currently, the role remains unknown.

Methods

Patients with gastric cancer who received curative operation with D2 dissection were enrolled in this study. Adjuvant chemotherapy was administered at the discretion of the physician. According to BRCA1 nuclear expression analysis by immunohistochemistry (IHC) on tissue microarrays using anti-BRCA1 antibody MS110, BRCA1 expression was classified as negative, low expression, and high expression.

Results

Among 318 cases, 155 cases (48.7 %) were identified as BRCA1-negative by IHC and 96 cases (30.2 %) revealed BRCA1 low expression, 67 cases (21.0 %) showed BRCA1 high expression. The negative or reduced expression of BRCA1 was more frequent in more advanced-stage disease (p < 0.001) and was associated with perineural invasion (p = 0.032). Disease-free survival (DFS) was significantly decreased with reduced BRCA1 expression (p = 0.027). This tendency was also observed in overall survival (OS), although the difference was not significant. The poorer prognosis of BRCA1-negative tumors was overcome through adjuvant chemotherapy. The benefit of adjuvant chemotherapy for DFS and OS in stage III was enhanced only in BRCA1-negative tumors (p < 0.001, p < 0.001, respectively), but not in BRCA1-positive tumors (p = 0.236, p = 0.148, respectively).

Conclusion

The reduction of BRCA1 nuclear expression is associated with advanced stage and perineural invasion. Moreover, negative BRCA1 nuclear expression is a predictive marker regarding the benefit of adjuvant chemotherapy in sporadic gastric cancer; these novel findings are of great importance, and further, larger studies are warranted.     

Molecular classification of breast carcinomas by comparative genomic hybridization: a specific somatic genetic profile for BRCA1 tumors

In approximately 70% of the families with a high frequency of early-onset breast and/or ovarian cancer, BRCA1 or BRCA2 germline mutations cannot be identified with the current screening regime. Therefore, we used data mining to identify a somatic genetic signature to differentiate BRCA1 mutation carriers from non-BRCA1 carriers based on the genetic characteristics of their breast carcinomas. For this purpose, we developed a molecular classifier, which assigns a given tumor to either the BRCA1 or control group based on somatic genetic profiles as revealed by comparative genomic hybridization. This was performed on breast tumors selected from two groups of patients: 28 proven BRCA1 germline mutation carriers; and a control group consisting of 42 breast tumors from patients with unknown BRCA1 or BRCA2 status. We show that BRCA1 breast carcinomas exhibit specific somatic genetic aberrations and can be distinguished from control tumors with an accuracy of 84% (sensitivity of 96% and specificity of 76%). Chromosomal bands used by this classifier include regions on chromosomes 3p, 3q, and 5q. The classifier miss-assigned one patient with a BRCA1 mutation to the non-BRCA1 class. The germline mutation in this patient is a 62bp deletion in the last exon of BRCA1 (5622del62). Possibly, this mutation may give a different phenotypic effect than do mutations in other regions of the gene. Validation on an independent set of BRCA1 and sporadic tumors showed that the BRCA1 classifier correctly identified all 6 BRCA1 tumors and assigned 4 of the 19 control patients to the BRCA1 class. The resulting accuracy on the validation set is 84%.     

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.