Lewis antigen alterations in gastric cancer precursors.

To explore the dynamics of the progressive loss of cell differentiation observed in the gastric precancerous process, the abnormal expression of Lea antigen in the gastric epithelium was investigated. Gastric biopsy specimens of 122 subjects with Le(a-b+) phenotype who had intestinal metaplasia of the gastric mucosa were studied. The subjects are residents of a rural area in the Colombian Andes with very high risk of gastric cancer. The abnormality was detected with increasing frequency in lesions with other markers of progression of the precancerous process, namely, colonic-type of morphology of the metaplastic cells, expression of sulfomucins, and dysplastic changes. The concomitant expression of the abnormal Lea antigen and sulfomucins was found to be a more reliable marker of more advanced lesions such as colonic metaplasia and dysplasia than either marker alone.