title: Promoter methylation and expression changes ofBRCA1in cancerous tissues of patients with sporadic breast cancer.
abstract: BRCA1is a susceptibility gene that has a genetic predisposition for breast cancer.BRCA1gene mutation is closely associated with familial hereditary breast cancer, but theBRCA1gene mutation is rarely found in sporadic breast cancer. According to previous studies, decreased expression ofBRCA1was detected in certain types of sporadic breast cancer. Aberrant methylation of DNA promoter CpG islands is one of the mechanisms by which tumor suppressor gene expression and function is lost. The aim of the present study was to investigateBRCA1gene expression, methylation status and clinical significance in sporadic types of breast cancer. Quantitative polymerase chain reaction (PCR) and bisulfite sequencing PCR were respectively used to detect expression differences ofBRCA1mRNA andBRCA1methylation in the 49 cancerous and paired non-cancerous samples from patients with breast cancer. The associations ofBRCA1expression and methylation status with the clinicopathologic characteristics were analysed.BRCA1mRNA expression levels in the 49 breast cancer tissues were lower than those in the paired non-cancerous tissues. There was a significant statistical difference (P=0.001).BRCA1mRNA expression was not associated with the main clinicopathologic characteristics. Frequency of theBRCA1promoter methylation in the breast cancerous tissues was significantly higher than that in the non-cancerous tissues (P=0.007);BRCA1gene methylation status was negatively correlated with mRNA expression (P=0.029); andBRCA1methylation exhibited no association with all clinicopathological features. DNA promoter hypermethylation may be the potential mechanism accounting forBRCA1expression silence in part of sporadic types of breast cancer. Some patients with hypermethylatedBRCA1may display favorable clinicopathological status.
authors: Department of Breast Surgery, The Affiliated Tumor Hospital of Guangxi Medical University, Guangxi 530021, P.R. China ; Department of General Surgery, No. 303 Hospital of PLA, Nanning, Guangxi 530021, P.R. China.
authors: Qiuyun
authors: Q
authors: Li
authors: Department of Breast Surgery, The Affiliated Tumor Hospital of Guangxi Medical University, Guangxi 530021, P.R. China.
authors: Wei
authors: W
authors: Wei
authors: Department of Breast Surgery, The Affiliated Tumor Hospital of Guangxi Medical University, Guangxi 530021, P.R. China.
authors: Y I
authors: YI
authors: Jiang
authors: Department of Breast Surgery, The Affiliated Tumor Hospital of Guangxi Medical University, Guangxi 530021, P.R. China.
authors: Huawei
authors: H
authors: Yang
authors: Department of Breast Surgery, The Affiliated Tumor Hospital of Guangxi Medical University, Guangxi 530021, P.R. China.
authors: Jianlun
authors: J
authors: Liu
keywords: BRCA1; DNA methylation; breast cancer