[Significance of CEA in gastric and colorectal cancer]

The determination of serum CEA (Sandwich method) and CEA staining (PAP method) of excised specimens were performed in patients with gastric or colorectal cancer, and the biological characteristics of each cancer and the factors to increase serum CEA were studied with the following results: As colonic cancer has strong CEA productivity, serum CEA can be useful for the detection of cancer, and especially effective for the postoperative observation. Gastric cancer has weak CEA productivity, and serum CEA is not so useful in the detection of cancer and the judgement of resectability. The CEA positive rate of tissue with CEA staining was 80% in gastric cancer, 100% in colonic cancer, and were nearly equal to the CEA positive rate of serum in the group of terminal stage. In the mode of CEA staining of cancerous cells, IV type was observed most frequently in gastric cancer, and I type in colonic cancer. Among the resected cases showing more than 7ng/ml serum CEA, differentiated type, lymph node metastasis (+), the degree of tissue staining with CEA staining, the mode of cell staining O or I type in gastric cancer and I type in colonic cancer were observed in common.