Biochemical markers in colorectal cancer: diagnostic and therapeutic implications.

Markers that are now in use, including CEA and CA-19-9, are not specific or sensitive enough to detect early colorectal cancer. Newer tumor markers such as polyamines, ornithine decarboxylase, and altered blood group carbohydrate antigens may have a potential as future tumor markers. Additional studies of these markers as well as the development of new biochemical markers are warranted in the future to enhance the sensitivity and specificity of diagnosis of early colorectal cancer and those at risk for developing cancer. Finally, understanding events involved in abnormal cell proliferation (that is, elevated polyamines and ODC in colorectal cancer) may help direct future chemotherapy and possibly chemoprevention in high-risk groups such as adenomatous polyposis coli.