Expression of type 1 and type 2 blood group-related antigens in normal and neoplastic gastric mucosa.

The distribution of the blood group-related antigens type 1 (Lewis(a) [Le(a)], Lewis(b) [Le(b)]) and type 2 (H type 2, Y) has been examined in histologically normal and malignant mucosa of 40 surgical specimens of patients with adenocarcinoma of the stomach, with the use of a panel of monoclonal antibodies. Patients' Lewis phenotype and secretor status are correlated to the authors' findings. The surface epithelium of normal pyloric and fundic mucosa expressed the Lewis isoantigen (Le(a) in Le[a+b-] phenotype and Le(b) in Le[a-b+] phenotype), whereas the deep areas of this mucosa no showed the Le(a), Le(b) antigens and expressed the Y and H type 2 antigens whatever the secretor status of patients. Nineteen of 24 patients with Le(a-b+) phenotype showed anomalous expression of Lea antigen in neoplastic cells. In three of them, this alteration was found in tumor adjacent mucosa. No expression of Le(a) or Le(b) antigens was found in tumors or normal mucosa from Le(a-b-) phenotype patients.