Variation in the penetrance estimates for BRCA1 and BRCA2 mutation carriers suggests that other genetic polymorphisms may modify the cancer risk in carriers. The RAD51 gene, which participates in homologous recombination double-strand breaks (DSB) repair in the same pathway as the BRCA1 and BRCA2 gene products, is a candidate for such an effect. A single-nucleotide polymorphism (SNP), RAD51-135g → c, in the 5′ untranslated region of the gene has been found to elevate breast cancer (BC) risk among BRCA2 carriers. We genotyped 309 BRCA1/2 mutation carriers, of which 280 were of Ashkenazi origin, 166 noncarrier BC patients and 152 women unaffected with BC (a control group), for the RAD51-135g → c SNP. Risk analyses were conducted using COX proportional hazard models for the BRCA1/2 carriers and simple logistic regression analysis for the noncarrier case–control population. BRCA2 carriers were also studied using logistic regression and Kaplan–Meier survival analyses. The estimated BC hazard ratio (HR) for RAD51-135c carriers adjusted for origin (Ashkenazi vs non-Ashkenazi) was 1.28 (95% CI 0.85–1.90, P=0.23) for BRCA1/2 carriers, and 2.09 (95% CI 1.04–4.18, P=0.04) when the analysis was restricted to BRCA2 carriers. The median BC age was younger in BCRA2-RAD51-135c carriers (45 (95% CI 36–54) vs 52 years (95% CI 48–56), P=0.05). In a logistic regression analysis, the odds ratio (OR) was 5.49 (95% CI 0.5–58.8, P=0.163). In noncarrier BC cases, carrying RAD51-135c was not associated with BC risk (0.97; 95% CI 0.47–2.00). These results indicate significantly elevated risk for BC in carriers of BRCA2 mutations who also carry a RAD51-135c allele. In BRCA1 carriers and noncarriers, no effect for this SNP was found.

Background: The risks for cancers other than breast (BC) or ovarian (OC) cancer in breast cancer gene 1 and 2 (BRCA1/2) mutation carriers were elevated in studies of carrier families. However, case–control studies did not confirm this observation. Objective: To compare the risks for other cancers in BRCA1/2 mutation carriers and non-carriers, all affected with BC and/or OC. Both groups share risk modifiers of BC/OC, which enabled assessment of the role of BRCA1/2 mutations. Methods: 1098 Ashkenazi Jewish women affected with BC and/or OC were ascertained during 1995–2003; molecular testing revealed 229 BRCA1 and 100 BRCA2 carriers and 769 non-carriers. COX proportional hazard models were used to evaluate the risk of other cancers. Analyses were conducted including all other cancers or only those diagnosed after BC/OC diagnosis. Results: The HRs for any other cancer were 2.6 (95% CI 1.7 to 4.2, p<0.001) and 1.8 (95% CI 0.95 to 3.6, p = 0.07) in BRCA1 and BRCA2 carriers, respectively. The corresponding colon cancer HRs were 3.9 (95% CI 1.3 to 12.1, p = 0.02) and 2.3 (95% CI 0.5 to 11.3, p = 0.3) in BRCA1 and BRCA2 carriers. The HR for lymphoma was 11.9 (95% CI 3.1 to 46.2, p = 0.001) in BRCA2 carriers. Risk estimates for other cancers after the onset of BC/OC were similar. Conclusion: A 2.5-fold increase in any other cancer and a fourfold risk of colon cancer were found among BRCA1 carriers. The corresponding HRs in BRCA2 carriers were non-significant, except for the markedly elevated risk of lymphoma. These results suggest a role for BRCA1/2 mutations in colorectal cancer risk in a subgroup of BC/OC-affected carriers.

It was shown that immunocompromised patients have significantly reduced immunologic responses to COVID-19 vaccines. The immunogenicity of COVID-19 vaccine/infection in patients with solid tumors is reduced. We evaluated the immunologic response to COVID-19 and/or the BNT162b2 mRNA COVID-19 vaccine among cancer patients on active treatments and reviewed previous literature to identify subgroups that may require third vaccination. Anti-SARS-CoV-2 S1/S2 antibodies were measured in a cohort of 202 cancer patients on active treatment with chemotherapy (96), immunologic (52), biologic (46), and hormonal (12) treatments for early (n = 66, 32.7%) or metastatic disease (n = 136, 67.3%). Of those, 172 had received two vaccine doses, and 30 had COVID-19 infection (20/30 also received one dose of vaccine). Specific anti-S receptor-binding domain antibodies were further measured in patients with equivocal anti-S1/S2 results. Among cancer patients, the SARS-CoV-2 antibody response rate was 89.1% (180/202) after COVID-19 vaccination or infection and 87.2% (150/172) in patients after vaccination without a history of COVID-19, compared with 100% positive serologic tests in a control group of 30 health care workers (P < 0.001). Chemotherapy treatment was independently associated with significantly reduced humoral response to infection or vaccination, with an 81.3% response rate, compared with 96.2% in patients on other treatments (P = 0.001). In vaccinated patients on chemotherapy, the positive response rate was 77.5%. In a multiple regression model, a neutralizing antibody titer (>60 AU/ml) was more likely with immunotherapy (odds ratio 2.44) and less likely with chemotherapy (odds ratio 0.39). Overall, both COVID-19 vaccine and natural infection are highly immunogenic among cancer patients. Our study, however, identifies those under chemotherapy as significantly less responsive, and with lower antibody levels. These findings justify close virological and serological surveillance along with consideration of these patients for booster (third dose) vaccine prioritization, as new highly spreading SARS-CoV-2 variants emerge.