Tumor markers are proteins, antigens, or enzymes that are produced by cancer cells or by the body in response to cancer. These markers can be detected in blood, urine, or tissues and can provide important information about the presence and type of cancer. For example, elevated levels of prostate-specific antigen (PSA) may indicate prostate cancer, while high levels of CA-125 can be associated with ovarian cancer. It is important to note that tumor markers are not definitive on their own and are usually used in conjunction with other diagnostic tests.
