Prostate-Specific Antigen-Expressing Tumor Cell

Prostate-specific antigen (PSA) is a protein produced almost exclusively by epithelial cells of the prostate gland, both in normal and malignant states. Tumor cells that express PSA are typically of prostatic origin, and PSA expression is a hallmark used to identify prostate cancer cells in tissue samples and blood. PSA immunohistochemistry is highly sensitive and specific for identifying prostatic origin of tumor cells. Lower levels or loss of apical staining pattern for PSA within tumors are associated with more aggressive disease features and poorer prognosis. Serum PSA measurement is widely used to monitor disease progression, response to therapy, recurrence after treatment.