Loss of MUC2 expression predicts disease recurrence and poor outcome in colorectal carcinoma

Clinical staging and histological grading after surgery have been the "gold standard" for predicting prognosis and planning for adjuvant therapy of colorectal cancer (CRC). With the recent development of molecular markers, it has become possible to characterize tumors at the molecular level. This is important for stage II and III CRCs, in which clinicopathological features do not accurately predict heterogeneity, e.g., in their tumor response to adjuvant therapy. In the present study, archival samples from 141 patients with stage I, II, III, or IV CRC treated during 1981-1990 at Turku University Hospital (Finland) were used (as microarray blocks) to analyze MUC2 expression by immunohistochemistry. Altogether, 49.7 % of all tumors were positive for MUC2. There was no significant correlation between MUC2 expression and age (P < 0.499), tumor invasion (P < 0.127), tumor staging (P < 0.470), histological grade (P < 0.706), lymph node involvement (P < 0.854), or tumor metastasis (P < 0.586). However, loss of MUC2 expression was significantly associated with disease recurrence (P < 0.031), tumor localization (P < 0.048), and with borderline significance with gender (P < 0.085). In univariate (Kaplan-Meier) survival analysis, positive MUC2 significantly predicted longer disease-free survival (DFS) and disease-specific survival (DSS) as well. However, in multivariate (Cox) survival analysis, MUC2 lost its power as an independent predictor of DFS and DSS. Our results implicate the value of MUC2 expression in predicting disease recurrence and long-term survival in CRC.