PCDHB15 As a Potential Tumor Suppressor and Epigenetic Biomarker for Breast Cancer

Breast cancer is among the most frequently diagnosed cancer types and the leading cause of cancer-related death in women. The mortality rate of patients with breast cancer is currently increasing, perhaps due to a lack of early screening tools. In the present study, using The Cancer Genome Atlas (TCGA) breast cancer dataset (n=883), it was determined that methylation of the protocadherin β15 () promoter was higher in breast cancer samples than that in normal tissues. A negative association between promoter methylation and expression of was observed in the TCGA dataset and breast cancer cell lines. In TCGA cohort, lower expression was associated with shorter relapse-free survival times. Treatment with the DNA methyltransferase inhibitor restored expression in a breast cancer cell line; however, overexpression of was shown to suppress colony formation. methylation detected in circulating cell-free DNA (cfDNA) isolated from serum samples was higher in patients with breast cancer (40.8%) compared with that in patients with benign tumors (22.4%). methylation was not correlated with any clinical parameters. Taken together, is a potential tumor suppressor in cases of breast cancer, which can be epigenetically silenced via promoter methylation. methylation using cfDNA is a novel minimally invasive epigenetic biomarker for the diagnosis and prognosis of breast cancer.