Leukocyte migration studies in gastric cancer detection: an approach toward improved specificity and sensitivity.

Peripheral blood leukocytes from patients with gastric cancer and various other malignant and nonmalignant diseases and peripheral blood leukocytes from apparently healthy volunteers were tested in the leukocyte migration inhibition test with the use of 4-5 different 3 M KCl extracts of gastric cancer tissue. An operational criterion for defining sensitization of patients' leukocytes was developed; i.e., evidence in an individual sample of leukocytes of either decreased or increased migration areas (migration index less than or equal to 0.79 and larger than or equal to 1.20, respectively) with 3 or more antigen extracts. With this as an indicator of sensitization, it was found that 91% of patients with gastric cancer (39/43), comparto 5% (5/94) and 3% (1/32) of patients with nonmalignant, nongastric diseases and normal controls, respectively, were reactive. Patients with various nongastric cancers were sensitized in 36% (49/135) of cases. Gastritis and gastric, as well as duodenal, ulcer did not influence the reactivity of patients' leukocytes, but considerable sensitization was found in patients with atrophic gastritis or intestinalization. When classified in the usual manner, i.e., by considering the reaction with individual tumor extracts, the specificity and the sensitivity of the test was markedly diminished: More false negative determinations were found in the group of gastric cancer patients, and the percentage of false positives in the group of nonmalignant diseases increased. The results gave evidence of tumor-associated antigens in gastric cancer patients, against which the host elicited a cellular immune response. The high incidence of positive reactivity of leukocytes from patients with gastric cancer, together with the considerable cross-reactivity of leukocytes from patients with nongastric cancer, pointed to the expression of antigens with organ-related and widespread specificities.