Significance of MUC1 and MUC2 mucin expression in colorectal cancer.

AIMS To compare the lineage specific distribution of MUC1 and MUC2 mucins in normal colorectal mucosa and adenocarcinoma and to identify pathological correlations. METHODS Paraffin wax sections from 51 colorectal cancers were examined for the expression of MUC1 and MUC2, non-O-acetyl sialic acid and the carbohydrate epitopes Lex, Ley, sialosyl-Lex, sialosyl-Tn, and Tn using standard histochemical methods. RESULTS MUC1, Lex and Ley co-localised with columnar cell secretions, whereas MUC2, mild periodic acid Schiff and sialosyl-Tn co-localised with goblet cell mucin in both normal and malignant tissues. Sialosyl-Lex and Tn were associated with both lineages. In normal tissues MUC1, Lex and Ley showed only trace expression by crypt base columnar cells. Cancers could be classified into four phenotypes (MUC2+/MUC1-, MUC2+/MUC1+, MUC2-/MUC1+, MUC2-/MUC1-). Particular phenotypes showed significant correlations with cancer type, lymph node spread and peritumoral lymphocytic infiltration and trends falling short of significance in relation to grade of differentiation and contiguous adenoma. CONCLUSIONS Classification of colorectal cancer by means of lineage specific function may be relevant to both pathogenesis and prognosis.