1. increased proliferation of well differentiated cells and/or uncontrolled elaboration of normal products, e.g.,
   1. hormones from primary endocrine tumors
   2. molecularly homogeneous immunoglobulins (monoclonal gammopathies) from malignant plasma cells
   3. acid phosphatase and PSA from prostatic cancer
   4. carcinoembryonic antigen (CEA) from colo-rectal carcinoma
2. dedifferentiation and elaboration of "abnormal" substances, e.g.,
   1. ectopic hormone elaboration from "APUDomas" ACTH, ADH, PTH; rare - TSH; never - T4, steroids
   2. embryonic, fetal, or placental proteins
      • chorionic gonadotropin (normally elaborated by trophoblastic tissue following conception)
      • CEA (a normal glycoprotein component of the plasma membrane of fetal intestine, pancreas, and liver)
      • alpha fetoprotein (synthesized by the yolk sac and the fetal liver - normal "albumin" of the fetus)
      • Regan alkaline phosphatase isoenzyme (normally synthesized by the placenta and trophoblasts)

Tumor markers are generally not specific indicators for a particular type of tumor, or even for the presence of a tumor. Neoplastic markers are tumor-associated, rather than tumor-specific, and are, therefore, not generally useful for cancer screening, but are mostly useful for monitoring the response to therapy:

CEA for resection of colorectal carcinoma

alpha feto protein for resection of hepatoma and teratoma

beta hCG for resection of choriocarcinoma and teratoma

Last Updated on 12/04/2014