Prostate-specific antigen expression in nipple aspirate fluid is associated with advanced breast cancer

We previously demonstrated that prostate-specific antigen (PSA) is present in breast nipple aspirate fluid (NAF) and its expression is inversely associated with the presence of breast cancer. The purpose of this study was to determine if PSA levels in NAF decrease with disease progression from DCIS to metastatic breast cancer. One hundred and forty-nine women underwent nipple aspiration before or in conjunction with surgery to treat their breast cancer. PSA levels decreased with more advanced disease stage (P = 0.016), larger tumor size (P = 0.031), and nodal involvement (P = 0.041). PSA levels were lower in women with than without distant disease spread (P = 0.049). We also evaluated the association of PSA with these clinical parameters based on menopausal status. In general, PSA predicted disease involvement better in pre- than in post-menopausal women. There was no association between PSA and race. Spearman's rank analysis demonstrated that PSA was inversely related to tumor size (P = 0.009), nodal status (P = 0.005), disease stage (P = 0.004), and distant metastases (P = 0.04). NAF PSA provides useful prognostic information which may assist with breast cancer treatment.