AT First Diagnostic Cancer Marker Tests: These are immunological methods - cancer markers that are produced as cancer grows and are detectable even before it reaches a size big enough for detection by other methods. This early detection system is vital for early medical intervention that significantly improves the chances of recovery.

Prostate specific antigen (PSA) is a serine protease that is found only in the prostate within the epithelial cells of the acini and ducts. Normal PSA concentration in whole blood or serum is 0.1-2.6 ng/ml. Reports have suggested that elevated level of whole blood or serum PSA is the must useful tumor markers in diagnosis of prostate cancers.

Alpha fetoprotein (AFP) levels are often elevated in liver cancers (hepatocellular) and testicular cancers (non-seminomatous). Raised levels are also present during pregnancy or some gastrointestinal cancers.

Carcinoembryonic antigen (CEA) is a cancer marker to screen for colorectal cancer - it is associated with digestive tract cancers (eg of the colon) as well as other malignant and non-malignant disorders. It is recommended for those with frequent constipation, diarrhea, or bleeding piles for an initial diagnostic tool. It can also help detect Medullary thyroid cancer (MTC).