is a susceptibility gene that has a genetic predisposition for breast cancer. gene mutation is closely associated with familial hereditary breast cancer, but the gene mutation is rarely found in sporadic breast cancer. According to previous studies, decreased expression of was 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 investigate gene 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 of mRNA and methylation in the 49 cancerous and paired non-cancerous samples from patients with breast cancer. The associations of expression and methylation status with the clinicopathologic characteristics were analysed. mRNA 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). mRNA expression was not associated with the main clinicopathologic characteristics. Frequency of the promoter methylation in the breast cancerous tissues was significantly higher than that in the non-cancerous tissues (P=0.007); gene methylation status was negatively correlated with mRNA expression (P=0.029); and methylation exhibited no association with all clinicopathological features. DNA promoter hypermethylation may be the potential mechanism accounting for expression silence in part of sporadic types of breast cancer. Some patients with hypermethylated may display favorable clinicopathological status.