Roni Milgrom

Common Breast Cancer-Predisposition Alleles Are Associated with Breast Cancer Risk in BRCA1 and BRCA2 Mutation Carriers

Germline mutations in BRCA1 and BRCA2 confer high risks of breast cancer. However, evidence suggests that these risks are modified by other genetic or environmental factors that cluster in families. A recent genome-wide association study has shown that common alleles at single nucleotide polymorphisms (SNPs) in FGFR2 (rs2981582), TNRC9 (rs3803662), and MAP3K1 (rs889312) are associated with increased breast cancer risks in the general population. To investigate whether these loci are also associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers, we genotyped these SNPs in a sample of 10,358 mutation carriers from 23 studies. The minor alleles of SNP rs2981582 and rs889312 were each associated with increased breast cancer risk in BRCA2 mutation carriers (per-allele hazard ratio [HR] = 1.32, 95% CI: 1.20-1.45, p(trend) = 1.7 x 10(-8) and HR = 1.12, 95% CI: 1.02-1.24, p(trend) = 0.02) but not in BRCA1 carriers. rs3803662 was associated with increased breast cancer risk in both BRCA1 and BRCA2 mutation carriers (per-allele HR = 1.13, 95% CI: 1.06-1.20, p(trend) = 5 x 10(-5) in BRCA1 and BRCA2 combined). These loci appear to interact multiplicatively on breast cancer risk in BRCA2 mutation carriers. The differences in the effects of the FGFR2 and MAP3K1 SNPs between BRCA1 and BRCA2 carriers point to differences in the biology of BRCA1 and BRCA2 breast cancer tumors and confirm the distinct nature of breast cancer in BRCA1 mutation carriers.

The rate of the predominant Jewish mutations in the BRCA1, BRCA2, MSH2 and MSH6 genes in unselected Jewish endometrial cancer patients

OBJECTIVES The genes associated with familial Endometrial Cancer (EC) are largely unknown. While EC is an integral part of Hereditary Non-Polyposis Colon Cancer, there is an ongoing debate if EC is indeed overrepresented in hereditary breast/ovarian cancer families. METHODS Unselected Jewish women with EC who were diagnosed from January 1982 to January 2008 were genotyped for the predominant mutations in Jewish individuals in BRCA1 (185delAG, 5382InsC, Tyr978X) BRCA2 (6174delT), MSH2 (A636P, 324delCA) and MSH6 (c.3984_3987dup). RESULTS Overall, 289 Jewish women with EC were included, the majority (217-75%) were Ashkenazim. Mean age at diagnosis was 62.6 ± 12 years, the most common histopathology was type I (endometrioid carcinoma) (80.4% of participants) with 29 having type II (Uterine papillary serous and clear cell cancer) Most patients (85.4%) had stage 1 disease by the FIGO staging. Five women (1.7%-2.3% of the Ashkenazim) carried either the BRCA1*185delAG (n = 4) or BRCA2*6174delT (n = 1) mutations, a rate similar with that of the general Ashkenazi population. Notably, none of 34 women with type II EC carried any BRCA1/BRCA2 mutations. Four (1.8%) and three (1.4%) of the 217 Ashkenazim patients harbored the c.3984_3987dup, A636P, MSH6 and MSH2 mutations, respectively, and 1/72 (1.4%) of the non-Ashkenazi patients harbored the 324delCA MSH2 mutation. Three of 42 (7.1%) women with EC diagnosed < 50 years carried either BRCA1 MSH6 or MSH2 mutations. CONCLUSIONS Our data do not support screening for BRCA1/2 mutations in consecutive EC patients.

SULT1E1 and ID2 genes as candidates for inherited predisposition to breast and ovarian cancer in Jewish women

Mutations in currently known genes account for only a subset of breast/ovarian cancer risk families. Three loci (2p, 4q, 22q) seemingly harbor breast cancer susceptibility genes. To explore their putative role in Jewish women, 46 affected women representing 22 high risk families were genotyped with D2S2211, D4S392, D22S278 and D22S283 and two flanking markers for each locus, and mutational analysis of ID2 (Chromosome 2) and SULT1E1 (Chromosome 4) genes was carried out in seemingly linked families. No ID2 gene mutations were detected in 8 women from the 4 families seemingly linked to D2S2211, whereas a missense mutation (His224Gln) in one affected woman from a single family was detected among 9 women from the 4 families linked to D4S392. This mutation was not found among 153 high risk, 98 sporadic breast/ovarian cancer patients, or 97 healthy controls. The SULT1E1 gene may need to be further explored as candidate breast cancer gene.