Tumour marker tests are chemicals made by tumour cells that can be detected in your blood.
Examples of tumour markers include prostate-specific antigen (PSA) for prostate cancer, cancer antigen 125 (CA 125) for ovarian cancer, calcitonin for medullary thyroid cancer, alpha-fetoprotein (AFP) for liver cancer and human chorionic gonadotropin (HCG) for germ cell tumours, such as testicular cancer and ovarian cancer.
Circulating tumour cell tests are blood tests used to detect cells that have broken away from an original cancer site and are floating in the bloodstream.
Useful Reading: