Biochemical tissue markers of human colorectal carcinoma

The potential therapeutic effects of differentiating agents on leukemic and solid tumor cells are being evaluated worldwide. These effects can be followed by morphologic as well as biochemical parameters. The enzymatic profile of four enzymes and the level of carcinoembryonic antigen were studied in 24 human colorectal carcinoma specimens and their adjacent uninvolved mucosa. The enzymes studied were thymidine kinase and 6-phosphogluconate dehydrogenase as markers of proliferation, and alkaline phosphatase and gamma-glutamyl transpeptidase as markers of differentiation. A consistent finding was a marked increase in the activities of thymidine kinase and 6-phosphogluconate dehydrogenase in the tumor cells as compared with the adjacent normal mucosa. The activity of gamma-glutamyl transpeptidase was not significantly different between tumor and uninvolved colon tissue. Alkaline phosphatase activity was markedly reduced in the tumor specimens. A relationship between the degree of differentiation and the degree of penetration and CEA expression was demonstrated in the tumor specimens as well as in their surrounding uninvolved mucosa.