Population-based germline breast cancer gene association studies and meta-analysis to inform wider mainstream testing.

BACKGROUND: Germline genetic testing, previously restricted to familial and young-onset breast cancer, is now offered increasingly broadly to 'population-type' breast cancer patients in mainstream oncology clinics, with wide variation in the genes included. METHODS: Weighted meta-analysis was performed for three population-based case-control studies (BRIDGES, CARRIERS and UK Biobank) comprising in total 101,397 women with breast cancer and 312,944 women without breast cancer, to quantify for 37 putative breast cancer susceptibility genes (BCSGs) the frequency of pathogenic variants (PVs) in unselected, 'population-type' breast cancer cases and their association with breast cancer and its subtypes. RESULTS: Meta-analysed odds ratios (ORs) and frequencies of PVs in population-type breast cancer cases were generated for BRCA1 (OR= 8.73 (95% CI 7.47-10.20), 1 in 101), BRCA2 (OR=5.68 (5.13-6.30), 1 in 68) and PALB2 (OR= 4.30 (95% CI 3.68-5.03), 1 in 187). For both CHEK2 (OR=2.40 (95% CI 2.21-2.62), 1 in 73) and ATM (OR=2.16 (95%CI 1.93-2.41), 1 in 132) subgroup analysis showed stronger association with ER-positive disease. Magnitude of association and frequency of PVs were low for RAD51C (OR=1.53 (95%CI 1.15-2.04), 1 in 913), RAD51D (OR=1.76, (95%CI 1.15-2.41, 1 in 1079) and BARD1 (OR=2.34 (1.85-2.97), 1 in 672); frequencies and associations were moderately higher restricting to triple-negative breast cancers The PV-frequency in 'population-type' breast cancer cases was very low for 'syndromic' BCSGs TP53 (1 in 1844), STK11 (1 in 11,525), CDH1 (1 in 2668), PTEN (1 in 3755) and NF1 (1 in 1470), with metrics of association also modest ranging from OR=3.62 (95%CI 1.98-6.61) for TP53 down to OR=1.60 (95%CI 0.48-5.30) for STK11. CONCLUSIONS: These metrics reflecting 'population-type' breast cancer will be informative to defining the appropriate gene set as we continue to expand to germline testing out to more unselected population-type breast cancer cases.

Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high-risk, early breast cancer.

BACKGROUND: The randomized, double-blind OlympiA trial compared 1 year of the oral poly(adenosine diphosphate-ribose) polymerase inhibitor, olaparib, to matching placebo as adjuvant therapy for patients with pathogenic or likely pathogenic variants in germline BRCA1 or BRCA2 (gBRCA1/2pv) and high-risk, human epidermal growth factor receptor 2-negative, early breast cancer (EBC). The first pre-specified interim analysis (IA) previously demonstrated statistically significant improvement in invasive disease-free survival (IDFS) and distant disease-free survival (DDFS). The olaparib group had fewer deaths than the placebo group, but the difference did not reach statistical significance for overall survival (OS). We now report the pre-specified second IA of OS with updates of IDFS, DDFS, and safety. PATIENTS AND METHODS: One thousand eight hundred and thirty-six patients were randomly assigned to olaparib or placebo following (neo)adjuvant chemotherapy, surgery, and radiation therapy if indicated. Endocrine therapy was given concurrently with study medication for hormone receptor-positive cancers. Statistical significance for OS at this IA required P < 0.015. RESULTS: With a median follow-up of 3.5 years, the second IA of OS demonstrated significant improvement in the olaparib group relative to the placebo group [hazard ratio 0.68; 98.5% confidence interval (CI) 0.47-0.97; P = 0.009]. Four-year OS was 89.8% in the olaparib group and 86.4% in the placebo group (Δ 3.4%, 95% CI -0.1% to 6.8%). Four-year IDFS for the olaparib group versus placebo group was 82.7% versus 75.4% (Δ 7.3%, 95% CI 3.0% to 11.5%) and 4-year DDFS was 86.5% versus 79.1% (Δ 7.4%, 95% CI 3.6% to 11.3%), respectively. Subset analyses for OS, IDFS, and DDFS demonstrated benefit across major subgroups. No new safety signals were identified including no new cases of acute myeloid leukemia or myelodysplastic syndrome. CONCLUSION: With 3.5 years of median follow-up, OlympiA demonstrates statistically significant improvement in OS with adjuvant olaparib compared with placebo for gBRCA1/2pv-associated EBC and maintained improvements in the previously reported, statistically significant endpoints of IDFS and DDFS with no new safety signals.

Analysis of mutation status and homologous recombination deficiency in tumors of patients with germline BRCA1 or BRCA2 mutations and metastatic breast cancer: OlympiAD.

BACKGROUND: Presence of a germline BRCA1 and/or BRCA2 mutation (gBRCAm) may sensitize tumors to poly(ADP-ribose) polymerase (PARP) inhibition via inactivation of the second allele, resulting in gene-specific loss of heterozygosity (gsLOH) and homologous recombination deficiency (HRD). Here we explore whether tissue sample testing provides an additional route to germline testing to inform treatment selection for PARP inhibition. PATIENTS AND METHODS: In this prespecified exploratory analysis, BRCA1 and/or BRCA2 mutations in blood samples (gBRCAm) and tumor tissue (tBRCAm) were analyzed from patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer and known gBRCAm, enrolled in the phase III OlympiAD trial. The frequency and nature of tBRCAm, HRD score status [HRD-positive (score ≥42) versus HRD-negative (score <42) using the Myriad myChoice® CDx test] and rates of gsLOH were determined, and their impact on clinical efficacy (objective response rate and progression-free survival) was explored. RESULTS: Tissue samples from 161/302 patients yielded tBRCAm, HRD and gsLOH data for 143 (47%), 129 (43%) and 125 (41%) patients, respectively. Concordance between gBRCAm and tBRCAm was 99%. gsLOH was observed in 118/125 (94%) patients [BRCA1m, 73/76 (96%); BRCA2m, 45/49 (92%)]. A second mutation event was recorded for two of the three BRCA1m patients without gsLOH. The incidence of HRD-negative was 16% (21/129) and was more common for BRCA2m (versus BRCA1m) and/or for hormone receptor-positive (versus triple-negative) disease. Olaparib antitumor activity was observed irrespective of HRD score. CONCLUSIONS: gBRCAm identified in patients with HER2-negative metastatic breast cancer by germline testing in blood was also identified by tumor tissue testing. gsLOH was common, indicating a high rate of biallelic inactivation in metastatic breast cancer. Olaparib activity was seen regardless of gsLOH status or HRD score. Thus, additional tumor testing to inform PARP inhibitor treatment selection may not be supported for these patients.

OlympiAD final overall survival and tolerability results: Olaparib versus chemotherapy treatment of physician's choice in patients with a germline BRCA mutation and HER2-negative metastatic breast cancer.

BACKGROUND: In the OlympiAD study, olaparib was shown to improve progression-free survival compared with chemotherapy treatment of physician's choice (TPC) in patients with a germline BRCA1 and/or BRCA2 mutation (BRCAm) and human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (mBC). We now report the planned final overall survival (OS) results, and describe the most common adverse events (AEs) to better understand olaparib tolerability in this population. PATIENTS AND METHODS: OlympiAD, a Phase III, randomized, controlled, open-label study (NCT02000622), enrolled patients with a germline BRCAm and HER2-negative mBC who had received ≤2 lines of chemotherapy for mBC. Patients were randomized to olaparib tablets (300 mg bid) or predeclared TPC (capecitabine, vinorelbine, or eribulin). OS and safety were secondary end points. RESULTS: A total of 205 patients were randomized to olaparib and 97 to TPC. At 64% data maturity, median OS was 19.3 months with olaparib versus 17.1 months with TPC (HR 0.90, 95% CI 0.66-1.23; P = 0.513); median follow-up was 25.3 and 26.3 months, respectively. HR for OS with olaparib versus TPC in prespecified subgroups were: prior chemotherapy for mBC [no (first-line setting): 0.51, 95% CI 0.29-0.90; yes (second/third-line): 1.13, 0.79-1.64]; receptor status (triple negative: 0.93, 0.62-1.43; hormone receptor positive: 0.86, 0.55-1.36); prior platinum (yes: 0.83, 0.49-1.45; no: 0.91, 0.64-1.33). Adverse events during olaparib treatment were generally low grade and manageable by supportive treatment or dose modification. There was a low rate of treatment discontinuation (4.9%), and the risk of developing anemia did not increase with extended olaparib exposure. CONCLUSIONS: While there was no statistically significant improvement in OS with olaparib compared to TPC, there was the possibility of meaningful OS benefit among patients who had not received chemotherapy for metastatic disease. Olaparib was generally well-tolerated, with no evidence of cumulative toxicity during extended exposure. Please see the article online for additional video content.

Homologous recombination deficiency and host anti-tumor immunity in triple-negative breast cancer.

PURPOSE: Triple-negative breast cancer (TNBC) is associated with worse outcomes relative to other breast cancer subtypes. Chemotherapy remains the standard-of-care systemic therapy for patients with localized or metastatic disease, with few biomarkers to guide benefit. METHODS: We will discuss recent advances in our understanding of two key biological processes in TNBC, homologous recombination (HR) DNA repair deficiency and host anti-tumor immunity, and their intersection. RESULTS: Recent advances in our understanding of homologous recombination (HR) deficiency, including FDA approval of PARP inhibitor olaparib for BRCA1 or BRCA2 mutation carriers, and host anti-tumor immunity in TNBC offer potential for new and biomarker-driven approaches to treat TNBC. Assays interrogating HR DNA repair capacity may guide treatment with agents inducing or targeting DNA damage repair. Tumor infiltrating lymphocytes (TILs) are associated with improved prognosis in TNBC and recent efforts to characterize infiltrating immune cell subsets and activate host anti-tumor immunity offer promise, yet challenges remain particularly in tumors lacking pre-existing immune infiltrates. Advances in these fields provide potential biomarkers to stratify patients with TNBC and guide therapy: induction of DNA damage in HR-deficient tumors and activation of existing or recruitment of host anti-tumor immune cells. Importantly, these advances provide an opportunity to guide use of existing therapies and development of novel therapies for TNBC. Efforts to combine therapies that exploit HR deficiency to enhance the activity of immune-directed therapies offer promise. CONCLUSIONS: HR deficiency remains an important biomarker target and potentially effective adjunct to enhance immunogenicity of 'immune cold' TNBCs.

Veliparib with temozolomide or carboplatin/paclitaxel versus placebo with carboplatin/paclitaxel in patients with BRCA1/2 locally recurrent/metastatic breast cancer: randomized phase II study.

Background: Homologous recombination defects in BRCA1/2-mutated tumors result in sensitivity to poly(ADP-ribose) polymerase inhibitors, which interfere with DNA damage repair. Veliparib, a potent poly(ADP-ribose) polymerase inhibitor, enhanced the antitumor activity of platinum agents and temozolomide in early phase clinical trials. This phase II study examined the safety and efficacy of intermittent veliparib with carboplatin/paclitaxel (VCP) or temozolomide (VT) in patients with BRCA1/2-mutated breast cancer. Patients and methods: Eligible patients ≥18 years with locally recurrent or metastatic breast cancer and a deleterious BRCA1/2 germline mutation were randomized 1 : 1 : 1 to VCP, VT, or placebo plus carboplatin/paclitaxel (PCP). Primary end point was progression-free survival (PFS); secondary end points included overall survival (OS) and overall response rate (ORR). Results: Of 290 randomized patients, 284 were BRCA+, confirmed by central laboratory. For VCP versus PCP, median PFS was 14.1 and 12.3 months, respectively [hazard ratio (HR) 0.789; 95% CI 0.536-1.162; P = 0.227], interim median OS 28.3 and 25.9 months (HR 0.750; 95% CI 0.503-1.117; P = 0.156), and ORR 77.8% and 61.3% (P = 0.027). For VT (versus PCP), median PFS was 7.4 months (HR 1.858; 95% CI 1.278-2.702; P = 0.001), interim median OS 19.1 months (HR 1.483; 95% CI 1.032-2.131; P = 0.032), and ORR 28.6% (P < 0.001). Safety profile was comparable between carboplatin/paclitaxel arms. Adverse events (all grades) of neutropenia, anemia, alopecia, and neuropathy were less frequent with VT versus PCP. Conclusion: Numerical but not statistically significant increases in both PFS and OS were observed in patients with BRCA1/2-mutated recurrent/metastatic breast cancer receiving VCP compared with PCP. The addition of veliparib to carboplatin/paclitaxel significantly improved ORR. There was no clinically meaningful increase in toxicity with VCP versus PCP. VT was inferior to PCP. An ongoing phase III trial is evaluating VCP versus PCP, with optional continuation single-agent therapy with veliparib/placebo if chemotherapy is discontinued without progression, in this patient population. Clinical trial information: NCT01506609.

Olaparib monotherapy in patients with advanced relapsed ovarian cancer and a germline BRCA1/2 mutation: a multistudy analysis of response rates and safety.

BACKGROUND: The PARP inhibitor olaparib (Lynparza™) demonstrates antitumor activity in women with relapsed ovarian cancer and a germline BRCA1/2 mutation (gBRCAm). Data from olaparib monotherapy trials were used to explore the treatment effect of olaparib in patients with gBRCAm ovarian cancer who had received multiple lines of prior chemotherapy. PATIENTS AND METHODS: This analysis evaluated pooled data from two phase I trials [NCT00516373 (study 2); NCT00777582 (study 24)] and four phase II trials [NCT00494442 (study 9); NCT00628251 (study 12); NCT00679783 (study 20); NCT01078662 (study 42)] that recruited women with relapsed ovarian, fallopian tube or peritoneal cancer. All patients had a documented gBRCAm and were receiving olaparib 400 mg monotherapy twice daily (capsule formulation) at the time of relapse. Objective response rate (ORR) and duration of response (DoR) were evaluated using original patient outcomes data for patients with measurable disease at baseline. RESULTS: Of the 300 patients in the pooled population, 273 had measurable disease at baseline, of whom 205 (75%) had received ≥3 lines of prior chemotherapy. In the pooled population, the ORR was 36% [95% confidence interval (CI) 30-42] and the median DoR was 7.4 months (95% CI 5.7-9.1). The ORR among patients who had received ≥3 lines of prior chemotherapy was 31% (95% CI 25-38), with a DoR of 7.8 months (95% CI 5.6-9.5). The safety profile of olaparib was similar in patients who had received ≥3 lines of prior chemotherapy compared with the pooled population; grade ≥3 adverse events were reported in 54% and 50% of patients, respectively. CONCLUSION: Durable responses to olaparib were observed in patients with relapsed gBRCAm ovarian cancer who had received ≥3 lines of prior chemotherapy. CLINICALTRIALSGOV: NCT00516373; NCT00494442; NCT00628251; NCT00679783; NCT00777582; NCT01078662.

Association of PHB 1630 C>T and MTHFR 677 C>T polymorphisms with breast and ovarian cancer risk in BRCA1/2 mutation carriers: results from a multicenter study.

BACKGROUND: The variable penetrance of breast cancer in BRCA1/2 mutation carriers suggests that other genetic or environmental factors modify breast cancer risk. Two genes of special interest are prohibitin (PHB) and methylene-tetrahydrofolate reductase (MTHFR), both of which are important either directly or indirectly in maintaining genomic integrity. METHODS: To evaluate the potential role of genetic variants within PHB and MTHFR in breast and ovarian cancer risk, 4102 BRCA1 and 2093 BRCA2 mutation carriers, and 6211 BRCA1 and 2902 BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA) were genotyped for the PHB 1630 C>T (rs6917) polymorphism and the MTHFR 677 C>T (rs1801133) polymorphism, respectively. RESULTS: There was no evidence of association between the PHB 1630 C>T and MTHFR 677 C>T polymorphisms with either disease for BRCA1 or BRCA2 mutation carriers when breast and ovarian cancer associations were evaluated separately. Analysis that evaluated associations for breast and ovarian cancer simultaneously showed some evidence that BRCA1 mutation carriers who had the rare homozygote genotype (TT) of the PHB 1630 C>T polymorphism were at increased risk of both breast and ovarian cancer (HR 1.50, 95%CI 1.10-2.04 and HR 2.16, 95%CI 1.24-3.76, respectively). However, there was no evidence of association under a multiplicative model for the effect of each minor allele. CONCLUSION: The PHB 1630TT genotype may modify breast and ovarian cancer risks in BRCA1 mutation carriers. This association need to be evaluated in larger series of BRCA1 mutation carriers.

Non-cancer endpoints in BRCA1/2 carriers after risk-reducing salpingo-oophorectomy.

Risk-reducing salpingo-oophorectomy (RRSO) significantly reduces the risk of ovarian cancer and breast cancer in pre-menopausal women with BRCA1 and BRCA2 (B1/2) mutations. Despite its clear benefits, little is known about non-cancer endpoints in this population. Medical records were examined in 226 B1/2 mutation carriers, who had previously undergone RRSO with a focus on bone health as well as the frequency of hypertension, hyperlipidemia, coronary artery disease (CAD), myocardial infarction (MI), diabetes, hypothyroidism and depression. From the medical records, DEXA scans, medications and medical conditions were recorded. Of the 226 patient records examined, 16% (36/226) had hypertension, 17% (39/226) hyperlipidemia, 2% (5/226) CAD or MI, 2% (4/226) diabetes, 13% (29/226) hypothyroidism and 14% (31/226) depression. DEXA results were available in 152 women. Of those DEXA scans, 71% (108/152) were abnormal (57% osteopenia and 14% osteoporosis). Among women who underwent RRSO prior to age 50, 71% (62/88) had osteopenia/osteoporosis. Although there was no difference in osteopenia/osteoporosis in women with RRSO prior to age 50 compared to those RRSO > 50, the age at follow up in these two groups differs greatly (mean age 44.7 vs. 60.6), suggesting that both current age and age at RRSO contribute to bone health assessment. In summary, here, we report the prevalence of non-cancer endpoints in a cohort of B1/2 mutation carriers and note a particularly high rate of osteopenia and osteoporosis in B1/2 with breast cancer undergoing RRSO prior to 50. Despite the risk reduction RRSO offers, attention should be paid to non-cancer endpoints, particularly bone health, in this population.

Exercise lowers estrogen and progesterone levels in premenopausal women at high risk of breast cancer.

Experimental and clinical data support a role for estrogens in the development and growth of breast cancer, and lowered estrogen exposure reduces breast cancer recurrence and new diagnoses in high-risk women. There is varied evidence that increased physical activity is associated with breast cancer risk reduction in both pre- and postmenopausal women, perhaps via lowered estrogen levels. The purpose of this study was to assess whether exercise intervention in premenopausal women at increased breast cancer risk reduces estrogen or progesterone levels. Seven healthy premenopausal women at high risk for breast cancer completed a seven-menstrual-cycle study. The study began with two preintervention cycles of baseline measurement of hormone levels via daily first-morning urine collection, allowing calculation of average area under the curve (AUC) hormone exposure across the menstrual cycle. Participants then began five cycles of exercise training to a maintenance level of 300 min per week at 80-85% of maximal aerobic capacity. During the last two exercise cycles, urinary estradiol and progesterone levels were again measured daily. Total estrogen exposure declined by 18.9% and total progesterone exposure by 23.7%. The declines were mostly due to decreased luteal phase levels, although menstrual cycle and luteal phase lengths were unchanged. The study demonstrated the feasibility of daily urine samples and AUC measurement to assess hormone exposure in experimental studies of the impact of interventions on ovarian hormones. The results suggest value in exercise interventions to reduce hormone levels in high-risk women with few side effects and the potential for incremental benefits to surgical or pharmacologic interventions.

Evaluation of the XRCC1 gene as a phenotypic modifier in BRCA1/2 mutation carriers. Results from the consortium of investigators of modifiers of BRCA1/BRCA2.

BACKGROUND: Single-nucleotide polymorphisms (SNPs) in genes involved in DNA repair are good candidates to be tested as phenotypic modifiers for carriers of mutations in the high-risk susceptibility genes BRCA1 and BRCA2. The base excision repair (BER) pathway could be particularly interesting given the relation of synthetic lethality that exists between one of the components of the pathway, PARP1, and both BRCA1 and BRCA2. In this study, we have evaluated the XRCC1 gene that participates in the BER pathway, as phenotypic modifier of BRCA1 and BRCA2. METHODS: Three common SNPs in the gene, c.-77C>T (rs3213245) p.Arg280His (rs25489) and p.Gln399Arg (rs25487) were analysed in a series of 701 BRCA1 and 576 BRCA2 mutation carriers. RESULTS: An association was observed between p.Arg280His-rs25489 and breast cancer risk for BRCA2 mutation carriers, with rare homozygotes at increased risk relative to common homozygotes (hazard ratio: 22.3, 95% confidence interval: 14.3-34, P<0.001). This association was further tested in a second series of 4480 BRCA1 and 3016 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2. CONCLUSIONS AND INTERPRETATION: No evidence of association was found when the larger series was analysed which lead us to conclude that none of the three SNPs are significant modifiers of breast cancer risk for mutation carriers.

Germline mutations in CDH1 are infrequent in women with early-onset or familial lobular breast cancers.

BACKGROUND: Germline mutations in CDH1 are associated with hereditary diffuse gastric cancer; lobular breast cancer also occurs excessively in families with such condition. METHOD: To determine if CDH1 is a susceptibility gene for lobular breast cancer in women without a family history of diffuse gastric cancer, germline DNA was analysed for the presence of CDH1 mutations in 318 women with lobular breast cancer who were diagnosed before the age of 45 years or had a family history of breast cancer and were not known, or known not, to be carriers of germline mutations in BRCA1 or BRCA2. Cases were ascertained through breast cancer registries and high-risk cancer genetic clinics (Breast Cancer Family Registry, the kConFab and a consortium of breast cancer genetics clinics in the United States and Spain). Additionally, Multiplex Ligation-dependent Probe Amplification was performed for 134 cases to detect large deletions. RESULTS: No truncating mutations and no large deletions were detected. Six non-synonymous variants were found in seven families. Four (4/318 or 1.3%) are considered to be potentially pathogenic through in vitro and in silico analysis. CONCLUSION: Potentially pathogenic germline CDH1 mutations in women with early-onset or familial lobular breast cancer are at most infrequent.

Breast cancer risks in individuals testing negative for a known family mutation in BRCA1 or BRCA2.

Genetic testing for BRCA1 and BRCA2 mutations in family members of individuals with known deleterious mutations can distinguish between patients at high risk of disease and those who are not. Some studies have suggested that individuals testing negative for known familial mutations (true negatives), may still have a higher risk of breast cancer (BC) than the general population. We have examined a prospectively followed cohort of true negative women in the US. Subjects were close relatives of known BRCA1 and BRCA2 mutation carriers who had undergone genetic testing, were negative for the known familial mutation, and were unaffected at the time of genetic testing. Standardized incidence ratios (SIR) and 95% confidence intervals (CI) were calculated using SEER incidence rates. Among 375 true negatives, two invasive and two in situ BC and no ovarian cancers were diagnosed with mean follow up of 4.9 years (total of 1,962 person years).Four invasive BC were expected, whereas two were observed, for an age-adjusted SIR of 0.52 (95% CI 0.13-2.09). We observed more cases of in situ BC (n = 2) than were expected (n = 0.9; SIR = 2.30; 95% CI 0.57-9.19).There were no cases of ovarian cancer observed; 0.4 case was expected. In this prospective study of women who were unaffected at the time of genetic testing and who were negative for the known familial mutation in BRCA1/2, no excess risk of invasive BC was observed. Our data suggest that such women in the US should adhere to population based guidelines for breast cancer screening.

Evaluation of a candidate breast cancer associated SNP in ERCC4 as a risk modifier in BRCA1 and BRCA2 mutation carriers. Results from the Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA).

BACKGROUND: In this study we aimed to evaluate the role of a SNP in intron 1 of the ERCC4 gene (rs744154), previously reported to be associated with a reduced risk of breast cancer in the general population, as a breast cancer risk modifier in BRCA1 and BRCA2 mutation carriers. METHODS: We have genotyped rs744154 in 9408 BRCA1 and 5632 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and assessed its association with breast cancer risk using a retrospective weighted cohort approach. RESULTS: We found no evidence of association with breast cancer risk for BRCA1 (per-allele HR: 0.98, 95% CI: 0.93-1.04, P = 0.5) or BRCA2 (per-allele HR: 0.97, 95% CI: 0.89-1.06, P = 0.5) mutation carriers. CONCLUSION: This SNP is not a significant modifier of breast cancer risk for mutation carriers, though weak associations cannot be ruled out.

The TP53 Arg72Pro and MDM2 309G>T polymorphisms are not associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers.

BACKGROUND: The TP53 pathway, in which TP53 and its negative regulator MDM2 are the central elements, has an important role in carcinogenesis, particularly in BRCA1- and BRCA2-mediated carcinogenesis. A single nucleotide polymorphism (SNP) in the promoter region of MDM2 (309T>G, rs2279744) and a coding SNP of TP53 (Arg72Pro, rs1042522) have been shown to be of functional significance. METHODS: To investigate whether these SNPs modify breast cancer risk for BRCA1 and BRCA2 mutation carriers, we pooled genotype data on the TP53 Arg72Pro SNP in 7011 mutation carriers and on the MDM2 309T>G SNP in 2222 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Data were analysed using a Cox proportional hazards model within a retrospective likelihood framework. RESULTS: No association was found between these SNPs and breast cancer risk for BRCA1 (TP53: per-allele hazard ratio (HR)=1.01, 95% confidence interval (CI): 0.93-1.10, P(trend)=0.77; MDM2: HR=0.96, 95%CI: 0.84-1.09, P(trend)=0.54) or for BRCA2 mutation carriers (TP53: HR=0.99, 95%CI: 0.87-1.12, P(trend)=0.83; MDM2: HR=0.98, 95%CI: 0.80-1.21, P(trend)=0.88). We also evaluated the potential combined effects of both SNPs on breast cancer risk, however, none of their combined genotypes showed any evidence of association. CONCLUSION: There was no evidence that TP53 Arg72Pro or MDM2 309T>G, either singly or in combination, influence breast cancer risk in BRCA1 or BRCA2 mutation carriers.

Prospective study of breast MRI in BRCA1 and BRCA2 mutation carriers: effect of mutation status on cancer incidence.

Annual MRI screening is recommended as an adjunct to mammography for BRCA1 and BRCA2 mutation carriers. Prophylactic oophorectomy has been shown to decrease breast cancer risk in BRCA1/2 mutation carriers. Here, we aimed to examine the combined effects of MRI and oophorectomy. For this purpose, 93 BRCA1/2 mutation carriers were screened with yearly mammograms and yearly MRI scans. Study endpoints were defined as date of breast cancer diagnosis, date of prophylactic mastectomy, or date of most recent contact. Of 93 women, with a median age of 47, 80 (86%) had prophylactic oophorectomy. Fifty-one women (55%) had BRCA1 mutations. A total of 283 MRI scans were performed. Eleven breast cancers (9 invasive, 2 ductal carcinoma in situ) were detected in 93 women (12%) with a median follow-up of 3.2 years (incidence 40 per 1,000 person-years). Six cancers were first detected on MRI, three were first detected by mammogram, and two were "interval cancers." All breast cancers occurred in BRCA1 mutation carriers (incidence 67 per 1,000 person-years). Apart from BRCA1 vs. BRCA2 mutation status, there were no other significant predictors of breast cancer incidence. Most invasive breast cancers were estrogen receptor negative (7 of 9) and lymph node negative (7 of 9). There have been no systemic recurrences with a median follow-up of 19 months after cancer diagnosis. Finally, it was concluded that all breast cancers occurred in BRCA1 mutation carriers, in most cases despite oophorectomy. These data suggest that surveillance and prevention strategies may have different outcomes in BRCA1 and BRCA2 mutation carriers.

Use of total abdominal hysterectomy and hormone replacement therapy in BRCA1 and BRCA2 mutation carriers undergoing risk-reducing salpingo-oophorectomy.

INTRODUCTION: Risk-reducing salpingo-oophorectomy (RRSO) reduces the risk of developing ovarian and breast cancer in BRCA 1 and BRCA 2 (BRCA1/2) mutation carriers. The short-term use of hormone replacement therapy (HRT) after RRSO may relieve menopausal symptoms and does not appear to affect the breast cancer risk reduction gained by RRSO. Multiple factors may influence decisions regarding whether or not total abdominal hysterectomy (TAH) is done at the time of RRSO, whether HRT is elected after surgery, and if so, which type of HRT is selected. Our investigation has been to examine factors associated with TAH and HRT use and to determine if the choice of TAH at the time of RRSO and the type of HRT that was chosen has changed since the report of data from the Women's Health Initiative (WHI) in 2002, which showed that the relative risk for breast cancer is higher in subjects who used combined estrogen-progestin HRT compared with those who used estrogen alone. METHODS: We identified 73 female BRCA1/2 mutation carriers who were known to have undergone RRSO between 1/1972 and 11/2005 who had no history of breast or ovarian cancer at the time of the surgery. Information regarding whether or not TAH was done in addition to RRSO, the type of HRT, and the subsequent diagnosis of breast cancer was collected. RESULTS: Of 73 unaffected BRCA1/2 carriers known to have had RRSO, 40 (40/73, 55%) also underwent TAH. Thirty-three of 73 (33/73, 45%) began HRT following RRSO. Of 33 HRT users, 17 (17/33, 52%) used estrogen only and 14 (14/33, 42%) used combined hormonal therapy. There was no difference in use of HRT in women with TAH (17/40, 43%) vs. those without (16/33, 48%) (P = 0.6). There was no difference in the proportion of women who underwent TAH before and after the WHI report in 2002. Use of HRT, most notably combined estrogen-progestin HRT, appears to have declined since 2002, although this result did not reach statistical significance. CONCLUSION: In this single institution study, the majority of BRCA1/2 mutation carriers undergoing RRSO also underwent TAH, and a substantial number took HRT. TAH did not increase the likelihood of taking HRT compared to RRSO alone.

Clinical management of BRCA1 and BRCA2 mutation carriers.

The cancer susceptibility genes BRCA1 and BRCA2 appear to be responsible for virtually all hereditary breast ovarian families, and a smaller subset of hereditary site-specific breast cancer families. Fortunately, effective strategies have been developed to reduce the risk for the development of breast and ovarian cancer in women with BRCA1/2 mutations, making genetic testing for these mutations an important part of the management at women with a strong family history of these diseases. Here, we review the current evidence for risk reduction strategies and outline future research directions.