In the pilot testing group, we analyzed by MS-HRMA for CST6 methylation 10 paired breast cancer and 10 adjacent non-cancerous (histologically normal) tissues, 7 histologically cancer-free specimens obtained from healthy women during reduction mammoplasty, and 9 breast fibroadenomas (included as a separate benign tumor group). The gene discussed is CST6; the disease is Fibroadenoma.