A comprehensive expression analysis of mucins in appendiceal carcinoma in a multicenter study: MUC3 is a novel prognostic factor

Background: Mucins are implicated in survival in various cancers, but there have been no report addressed on survival in appendiceal carcinoma, an uncommon disease with different clinical and pathological features from those of other colon cancers. We aimed to investigate the clinical implications of expression of mucins in appendiceal carcinoma. Methods: Expression profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC6, MUC16 and MUC17 in cancer tissue were examined by immunohistochemistry in 108 cases of surgically resected appendiceal carcinoma. Results: The following relationships of mucins with clinicopathologic factors were identified: MUC1 with positive lymphatic invasion (p=0.036); MUC2 with histological type (mucinous carcinoma, p<0.001), superficial invasion depth (p=0.007), negative venous invasion (p=0.003), and curative resection (p=0.019); MUC3 with non-curative resection (p=0.017); MUC5AC with histological type (mucinous carcinoma, p=0.002), negative lymphatic invasion (p=0.021), and negative venous invasion (p=0.022); and MUC16 with positive lymph node metastasis (p=0.035), positive venous invasion (p<0.05), and non-curative resection (p=0.035). A poor prognosis was related to positive lymph node metastasis (p=0.04), positive lymphatic invasion (p=0.02), positive venous invasion (p<0.001), non-curative resection (p<0.001), and positive expression of MUC3 (p=0.004). In multivariate analysis, positive venous invasion (HR: 6.93, 95% CI: 1.93-24.96, p=0.003), non-curative resection (HR: 10.19, 95% CI: 3.05-34.07, p<0.001) and positive MUC3 expression (HR: 3.37, 95% CI: 1.13-10.03, p=0.03) were identified as significant independent prognostic factors in patients with appendiceal carcinoma. Conclusions: Expression of MUC3 in appendiceal carcinoma is an independent factor for poor prognosis and a useful predictor of outcome in patients with appendiceal carcinoma after surgery.