To clarify the significance of immunoreactive carcinoembryonic antigen in gastric juice (gastric CEA) from gastric cancer patients, we studied the gastric CEA in comparison with cancer progress, histologic types of tumors, staining for CEA and extent of intestinal metaplasia. The gastric CEA levels from patients with other gastric diseases, i.e., gastric ulcer, duodenal ulcer and chronic gastritis were also investigated. The mean gastric CEA level from gastric cancer patients was significantly higher than from gastric or duodenal ulcer patients, but there was no significant difference between levels in patients with gastric cancer and in those with chronic gastritis. The gastric CEA levels from cancer patients increased with progression of the cancer. The differentiated carcinomas showed significantly higher gastric CEA levels than the poorly differentiated carcinomas. Positive CEA tumors showed significantly higher gastric CEA levels than did the negative CEA tumors. The tumors with diffuse intestinal metaplasia revealed high gastric CEA levels. Determination of gastric CEA levels is considered to be useful for screening of gastric cancer.

To obtain information regarding the immunologic capacity of uninvolved regional lymph nodes (RLNs) draining tumor, the in vitro response of regional lymph node cells (RLNCs) to PHA was investigated in lymph nodes from 55 patients with gastric or colorectal cancer, and gastric ulcer. Evaluation of data relative to cancer progress demonstrated that, in gastric cancer patients, the response of stimulated RLNCs from patients with middle stage carcinoma was significantly higher compared with those of cells from patients with early or late stage carcinoma, such being similar to the response of RLNCs from control patients with gastric ulcer. The results from colorectal cancer patients were also similar to those from patients with gastric cancer. Our results suggest that RLNs without metastasis contain cells capable of responding to PHA despite the presence of growing tumors in these cancer patients. In the results of PHA stimulation in relation to the lymph node morphology, we observed in both groups of patients with gastric or colorectal cancer that, regardless of the extent of the cancer lymph nodes with lymphocyte predominance there was a high PHA response while lymph nodes with lymphocyte depletion and unstimulated nodes exhibited a low PHA response. These results show a close relationship between this lymph node morphology and immunologic status of nodes.

Leucocytes from patients with gastric cancer and other malignant and non-malignant diseases of the gastrointestinal tract as well as from healthy controls were tested for leucocyte migration inhibition test (LMI) using five different, allogeneic 3M KCl soluble extracts from gastric cancer tissues. The normal range of migration index (MI) was considered to be between 0.77 and 1.18 by calculating the mean MI +/- 2SD of ten healthy controls with cancer extracts. MIs out of this range were considered to be pathologic. In LMI test with a single tumor extract, pathologic MI was found in 48% of 79 gastric cancer patients, such being significantly higher than in those (4-21%) of three other groups of patients. In the panel mode of LMI, i.e., testing each blood sample with five different tumor extracts, 79% (62/79) of patients with gastric cancer were reactive, while 25% (5/20) of colorectal cancer patients showed "positive" reaction and no "positive" reactivity was observed in two other groups of patients. Thus, the "positive" reactivity in patients with gastric cancer was observed significantly higher than those in the other 3 groups of patients. Gastric cancer extracts had a wide range of cross-reactivity when compared with colorectal tumor extracts which showed a relatively restricted cross-reactivity. Thus, the LMI tests, particularly when tested by a panel mode, seems to express cell-mediated immunity against tumor associated antigens of gastric cancer.

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