有研究曾发现，与乳腺癌有关的基因BRCA1发生变异会显着提高女性患乳腺癌的风险。由美国梅奥诊所领导的一个国际科研小组在新一期英国学术刊物《自然·遗传学》上报告说，当BRCA1基因发生变异使女性患乳腺癌的风险提高时，另外5个基因的变异会对这一风险产生影响。
研究人员进行的全基因组关联分析涉及11个国家的20个研究中心。第一组研究对象是1193名携带BRCA1变异基因且患有浸润性乳腺癌的40岁以下妇女。研究人员分析了上述妇女基因组中总共约55万个基因变异，然后将这些变异与第二组研究对象的全部基因变异进行对比分析。后者的总人数为1190名，她们都是携带BRCA1变异基因却没有患乳腺癌的同龄妇女。
随后，研究人员将基因分析的范围缩小到96个单核苷酸多态性（SNP），并在两个更大的样本中进行了类似对比。结果发现，位于19p13染色体某区域的5个基因的变异，与携带BRCA1变异基因的妇女患乳腺癌的几率密切相关。（生物谷Bioon.com）
生物谷推荐英文摘要：
Nature Genetics doi:10.1038/ng.669
A locus on 19p13 modifies risk of breast cancer in BRCA1 mutation carriers and is associated with hormone receptor–negative breast cancer in the general population
Antonis C Antoniou, Xianshu Wang, Zachary S Fredericksen et al.
Germline BRCA1 mutations predispose to breast cancer. To identify genetic modifiers of this risk, we performed a genome-wide association study in 1,193 individuals with BRCA1 mutations who were diagnosed with invasive breast cancer under age 40 and 1,190 BRCA1 carriers without breast cancer diagnosis over age 35. We took forward 96 SNPs for replication in another 5,986 BRCA1 carriers (2,974 individuals with breast cancer and 3,012 unaffected individuals). Five SNPs on 19p13 were associated with breast cancer risk (Ptrend = 2.3 × 10?9 to Ptrend = 3.9 × 10?7), two of which showed independent associations (rs8170, hazard ratio (HR) = 1.26, 95% CI 1.17–1.35; rs2363956 HR = 0.84, 95% CI 0.80–0.89). Genotyping these SNPs in 6,800 population-based breast cancer cases and 6,613 controls identified a similar association with estrogen receptor–negative breast cancer (rs2363956 per-allele odds ratio (OR) = 0.83, 95% CI 0.75–0.92, Ptrend = 0.0003) and an association with estrogen receptor–positive disease in the opposite direction (OR = 1.07, 95% CI 1.01–1.14, Ptrend = 0.016). The five SNPs were also associated with triple-negative breast cancer in a separate study of 2,301 triple-negative cases and 3,949 controls (Ptrend = 1 × 10(7) to Ptrend = 8 × 10(5); rs2363956 per-allele OR = 0.80, 95% CI 0.74–0.87, Ptrend = 1.1 × 10(7)).
