MUC1 and small intestine carcinoma: We also previously examined mucin expression in small intestinal carcinoma, and found positive expression rates of MUC1, 51.7%; MUC2, 26.7%; MUC3, 55.0%; MUC4, 51.7%; MUC5AC, 33.3%; MUC6, 10.0%; and MUC16, 8.3% (MUC17 expression was not examined) [17].