MUC13 and colorectal carcinoma: There have been discrepancies regarding MUC13 expression in CRC; Packer et al. and Williams et al. both reported a downregulation of MUC13 mRNA levels [95,101], while Walsh et al. and Gupta et al. reported MUC13 expression equal to or greater than paired normal samples in 100% of tumors evaluated by IHC [102,103].