MUC5AC and hyperplastic polyp: A total of 454 polyp specimens comprising 36 hyperplastic polyps, 15 serrated adenomas, 258 tubular adenomas, 114 tubulovillous adenomas, and 31 villous adenomas were included in this study, and were immunostained for MUC1, MUC2, MUC5AC and MUC6 by using mucin specific antibodies.