TTF1 and neoplasm: Therefore, the objectives of this study were: (1) to immunohistochemically examine MUC5B expression in tumor cells of 198 ACs and 49 SCCs, (2) to evaluate the relationships between MUC5B expression in tumor cells and the clinicopathological parameters of ACs, and (3) to estimate the diagnostic accuracy of combined MUC5B and TTF-1 expressions in ACs.