[Studies on carcinoembryonic antigen (CEA), lactate dehydrogenase (LDH), and LDH isozymes in the tissue of colorectal carcinoma].

Tissue carcinoembryonic antigen (CEA), lactate dehydrogenase (LDH) and LDH isozymes were measured to assess as tumor markers of colorectal cancer. Tissue samples were collected from carcinoma and the entire layers of normal colorectum at the distance of 1, 2, 4, 6 and 8 cm from the edge of carcinoma. The mean CEA content in cancer tissue was 18143 ng/g and the elevation of CEA content was found in normal tissue within 6 cm from the edge of carcinoma comparing to that in control materials, gradually decreased as the distance from carcinoma increased. LDH activity in cancer tissue was very high and its gradual decrease in normal tissue surrounding tumor with the distance from carcinoma was recognized. LDH isozyme ratio (LDH4 + LDH5/LDH1 + LDH2) and H subunit % (LDH1 + 3/4LDH2 + 1/2LDH5 + 1/4LDH) in cancer tissue were obviously different from those of control materials, LDH isozyme ratio in normal tissue within 4 cm from the edge of carcinoma and H subunit % within 6 cm showed the significant difference to those in control materials. The author concludes that the increase of tissue CEA content, LDH activity and the deviation of LDH isozymatic pattern in normal tissue could be early signs of malignancy before the morphologic changes.