12 super-minute lesions (less than 1 mm in maximum diameter) of well-differentiated adenocarcinoma in distal stomach (SMCa), which were detected from the pathological examinations of 210 surgically resected stomach specimens, and the mucosa adjacent to these carcinoma lesions, were examined by immunohistochemical mucin stainings (MUC2 and CD-10: intestinal phenotype, 45M1 and MUC6: gastric phenotype) and p53-overexpression. The gene discussed is MUC6; the disease is carcinoma.