GENETIC AND ENZYMATIC EVIDENCE FOR LEWIS ENZYME EXPRESSION IN LEWIS-NEGATIVE CANCER-PATIENTS

It has been observed that the frequency of individuals with Lewis-nega tive erythrocytes is significantly higher in cancer patients than in h ealthy controls. In this study, 20 of the 66 (30.3%) patients with var ious cancers were typed as Lewis negative from their erythrocytes, whi le the same frequency in healthy controls was 11.1%. These 20 patients were divided into three groups based on the presence of Lewis blood g roup antigens and alpha 1-->4-fucosyltransferase in their salivas: gro up I, 6 patients who had both Lewis antigens and alpha 1-4-fucosyltran sferase activity; group II, 8 patients who had no Lewis antigens but p ossessed alpha 1-->4-fucosyltransferase activity; group III, 6 patient s who had neither Lewis antigens nor alpha 1-->4-fucosyltransferase ac tivity. The genotyping of Le genes by the PCR-RFLP methods, which have been developed and established by us recently, demonstrated that all 14 patients from groups I and II possess Le gene homozygously (Le/Le) or heterozg gously (Le/le), whereas all 6 patients from group III were le/le homozygotes. Only the 6 patients from group In were identified as the genuine Lewis-negative individuals. The immunohistochemical sta ining of the colorectal tumors also showed that the Lewis antigens cou ld be detected on the tumors from groups I and II but not from group I II.