PIP: This study examined the levels of prostate specific antigen (PSA) in breast tumor tissue of patients who received progestin-containing oral contraceptives (OCs) 1 week prior to surgery. About 20 patients with primary breast cancer were enrolled in the study: 10 were not given any treatment before surgery and served as control subjects and 10 received OCs. Tumor tissue was excised during surgery and stored until extraction of PSA before biochemical analysis was performed. Post-surgical serum was obtained after 2 days. Tumor extract PSA levels were 80 ng/l in all samples tested. The exception was one patient who¿s tumor PSA level reached 1934 ng/l; this patient received OCs and had a serum PSA level of 26 ng/l, which decreased to 2 ng/l after tumor removal and OC discontinuation. Overall findings suggest that PSA levels are relatively low in all breast tumor extracts receptive of steroid hormone status, tumor stage or grade, lymph node status, patient age, or menopausal status.