PSA is a protein produced by the prostate gland; elevated levels may indicate prostate cancer or other prostate-related conditions like benign prostatic hyperplasia.
CA-125 is a protein elevated in ovarian cancer and certain other conditions; used to monitor treatment response and recurrence of ovarian cancer.
CEA is a protein found in some cancers, including colorectal cancer; elevated levels help in diagnosing, monitoring, and assessing cancer treatment effectiveness.
AFP is a protein produced by the liver and yolk sac; elevated levels may indicate liver cancer, germ cell tumors, or certain birth defects.