Serum AFP levels are elevated in patients with hepatoma, testicular germ cell tumours, ovarian germ cell tumours, pancreatic carcinoma, gastric carcinoma and colonic carcinoma. The most specific in vitro test for primary carcinoma of the liver is the serum AFP assay

CA 12-5 has an established role in the management of ovarian cancer, as prognostic indicator and in monitoring disease status. A large number of studies have confirmed that serum CA 12-5 levels are elevated pre-operatively in 80-85% of women with epithelial ovarian cancer

Patients with breast cancer have elevated values of CA 15-3. Besides monitoring, it is used to detect recurrent disease after primary therapy before it can be detected clinically.

The level of CA 19-9 is frequently elevated in serum or plasma of patients with intra-abdominal carcinomas. It is most strikingly correlated with the cancer of the pancreas where studies have shown a sensitivity of 90% and a specificity of 85%.

CA 19-9 may also be elevated in order adenocarcinomas such as lung, gastric, biliary and colonic.

Malignant C cell tumours (medullary thyroid carcinoma[MCT]) often produce elevated levels of calcitonin. MLT is not common, comprising about 7-10% of all thyroid malignancies.

Calcitonin levels may be elevated in some patients with cancer of the lung, breast, pancreas or in patients with chronic renal failure.

CEA in serum can be used as an aid in the prognosis and management of cancer patients. It has been shown to be of value in the follow-up management of patients with colorectal, breast, lung, prostatic, pancreatic and ovarian carcinoma.

Nasopharyngeal carcinoma, NPC is strongly associated with EBV. More than 90% of NPC patients have elevated antibodies to EBV determined antigens.

HCG is a useful tumour marker especially for monitoring gestational trophoblastic neoplasm and germ cell tumours of the testis and ovary.

PAP may be found to be elevated in the majority of patients with advanced or stage D prostatic cancer and correlates with the activity of the disease. Large amount of PAP appear in the blood with carcinoma of the prostate and particularly when there is metastases.

PSA is now used for assisting in the diagnosis of the prostatic carcinoma, although the blood levels of PSA can also be somewhat elevated in benign prostatic hypertrophy. In general, PSA and PAP together improve the diagnostic sensitivity over either one used alone. 

Further readings :

• Screening of cancer - NIH fact sheet
• Cancer Risk Assessment & Counseling Home Page
• Mayo Clinic Cancer Centre
• Cancer News on the Net
• Healthtouch - Tumor Markers Information from National Cancer Institute (NCI)
• Iowa Health Book: Cancer Tests You Should Know About
• Healthfinder guided tour -- cancer
• FDA article: Prostate cancer - No one answer for testing or treatment
• Breast cancer - Decision-making guidelines - Useful information from Mayo Clinic