Low expression of MUC2 is associated with longer disease-free survival in patients with colorectal carcinoma

Abstract

Background/aim: The objective of this study was to investigate the relationship between MUC2 immunostaining and clinicopathological characteristics in a subset of colorectal carcinomas (CRCs).

Materials and methods: A total of 128 CRCs, 50 local nodal metastases, and 42 normal colonic mucosae were retrieved from the archives at the Department of Pathology at King Abdulaziz University, Jeddah, Saudi Arabia. Immunohistochemistry was performed using anti-MUC2 antibody. A cut-off of 25% of positive immunostaining was used to define low and high immunostaining. Statistical tests were used to determine the association of MUC2 with clinicopathological characteristics and survival.

Results: MUC2 immunostaining was observed in 66.7% in normal colonic mucosa. Low MUC2 immunostaining was higher in primary CRC (P = 0.003) and nodal metastasis (80%) (P < 0.001). There was significant association of low MUC2 immunostaining in CRC with age group below 60 years (P = 0.05) and occurrence of lymphovascular invasion (P = 0.034). Other clinicopathological parameters were not correlated with MUC2 immunostaining. Regression analysis revealed that low MUC2 immunostaining was an independent predictor of lymphovascular invasion (P = 0.041). In the Kaplan-Meier survival analysis, there was a significant longer disease-free survival in patients with low MUC2 immunostaining (P = 0.045). However, there was no association between MUC2 immunostaining and overall survival (P = 0.601).

Conclusion: MUC2 immunostaining may have distinct clinical significance and provide valuable information and could be considered as an important independent prognostic factor while planning the adjuvant therapy in CRC. In future perspective, characterization of MUC2 immunostaining on a large number of cases and molecular studies may be needed.

Keywords: Colorectal carcinoma; MUC2; immunostaining; prognosis.

Figure 1

Immunostaining of MUC2. (a and b) Cytoplasmic immunostaining of MUC2 in the colonic crypts (100x). (c) A well-differentiated colorectal carcinoma showing strong MUC2 immunostaining (200x). (d) A poorly differentiated colorectal carcinoma showing low MUC2 immunostaining (100x). (e) A metastatic well-differentiated colorectal carcinoma showing absent MUC2 immunostaining (100x). (f) A metastatic colorectal carcinoma showing strong MUC2 immunostaining (100x) immunohistochemical labeling with anti-MUC2 antibody was done using diaminobenzidine as the chromogen and hematoxylin as counterstain

Figure 2

Disease-free survival curve (Kaplan–Meier) according to MUC2 immunostaining in colorectal carcinoma (1: Low MUC2 immunostaining; 2: High MUC2 immunostaining [log-rank = 4.0.12, P = 0.45])

Figure 3

Overall survival curve (Kaplan–Meier) according to MUC2 immunostaining in colorectal carcinoma (1: Low MUC2 immunostaining; 2: High MUC2 immunostaining [log-rank = 0.273, P = 601])