MUC1 and pancreatic ductal adenocarcinoma: Correspondingly, clear-cell papillary renal cell carcinomas [14], are positive for CD10 and negative for cytokeratin 7, prostatic carcinomas with abundant xanthomatous cytoplasm [16] show a strong prostate specific antigen positivity and finally, foamy gland patterns of pancreatic ductal adenocarcinoma [13] are diffusely positive for carcinoembryonic antigen, cytokeratin 8 and MUC1.