Epigenetic Modifiers of Breast Cancer Risk

描述（由申请人提供）：乳腺癌（BC）是一种复杂的疾病，具有遗传和环境原因，是女性癌症死亡的第二大原因。大多数患乳腺癌的女性（约70%）没有已知的家族史或明显的危险因素。其余30%的病例倾向于在家庭中聚集，其中5-7%是通过BRCA 1和BRCA 2突变遗传的，这是目前唯一可用于乳腺癌的基因检测。最近对乳腺导管上皮细胞和肿瘤组织的分子研究表明，存在几种DNA修复和肿瘤控制基因，其表达为功能蛋白质通过DNA甲基化被有效关闭或沉默。据推测，乳腺上皮细胞中沉默的肿瘤控制基因的存在可能预示着具有这种分子修饰的女性最终发展为BC。这项研究的具体目标是：1）鉴定与处于BC平均风险的女性的病例匹配对照队列相比，从处于BC高风险的女性队列中的乳腺肿瘤组织和周围健康乳腺组织分离的DNA中的甲基化抑制的肿瘤控制基因，以及2）确定家庭和个人因素对乳腺癌结果的预测性贡献，例如BC史，发病年龄、产次、初潮年龄、既往乳腺活检、内源性和外源性激素暴露、筛查史和BRCA突变状态。这项研究对改善风险评估具有意义，并可能最终帮助妇女在决策过程中进行筛查和降低风险的预防措施，如降低风险的乳房切除术和化学预防。

DESCRIPTION (provided by applicant): Breast cancer (BC) is a complex disease with both genetic and environmental causes, and is the second leading cause of cancer death in women. Most women who develop breast cancer (approximately 70%) have no known family history or obvious risk factors. The remaining 30% of cases tend to aggregate in families, and 5-7% of these are heritable through BRCA1 and BRCA2 mutations, the only gene tests currently available for breast cancer. Recent molecular studies of breast ductal epithelial cells and tumor tissue have demonstrated the presence of several DNA repair and tumor control genes whose expression into functional proteins is effectively shut down or silenced via DNA methylation. It is hypothesized that the presence of silenced tumor control genes in breast epithelial cells may presage the eventual development of BC in women with such molecular modifications. The specific aims of this research are: 1) to identify methylation suppressed tumor control genes in DNA isolated from breast tumor tissue and surrounding healthy breast tissue in a cohort of women at high risk for BC, as compared to a case-matched control cohort of women at average risk for BC, and 2) to determine the predictive contributions of family and personal factors on breast cancer outcome, such as a history of BC, age-of-onset, parity, age at menarche, previous breast biopsies, endogenous and exogenous hormone exposure, screening history, and BRCA mutation status. This research has implications for improving risk assessment, and may ultimately aid women in the decision-making process regarding screening and risk reduction prophylactic measures such as risk reduction mastectomy and chemoprevention.