Evaluation of mucin 1 expression and its correlation with grading and staging in colorectal carcinoma

Abstract

INTRODUCTION Colorectal cancer (CRC) is a leading cause of cancer-related deaths globally, with approximately two million new cases and one million deaths reported in 2020. In India, CRC incidence has been increasing, particularly in the northeastern and southern regions, due to genetic factors, lifestyle, and environmental factors. Over 50% of cases are diagnosed at an advanced stage, limiting treatment options and worsening prognosis. Biomarkers such as Carcinoembryonic Antigen, CD133, and Mucin-1 (MUC1) play crucial roles in CRC detection. MUC1, a transmembrane glycoprotein, is linked to aggressive tumor behavior and poor prognosis. It was also mentioned that MUC1 expression was significantly correlated with advanced tumor grade, depth of invasion and lymph node metastasis. Hence, this study was undertaken to correlate MUC1 expression with the grading and staging of CRC. OBJECTIVES To evaluate MUC1 expression in tumor tissue of CRC and to correlate it with grading and staging of CRC. MATERIAL AND METHODS A hospital-based cross-sectional study was done on 40 specimens received in the Histopathology Section. Tumor tissue blocks on which diagnosis of CRC was made were evaluated for MUC1 expression and were correlated with grading and staging of CRC. Scoring of MUC1 positivity was done as Score 3+, 2+ and 1+ based on percentage of MUC1 positivity. RESULTS MUC1 expression showed Score 3+ positivity in 70% cases of moderately differentiated adenocarcinoma, 50% cases of well-differentiated adenocarcinoma and in all cases of poorly differentiated adenocarcinoma. A maximum number of cases showing score 3 MUC1 expression were in stage T3 and T4, amounting to 78.57% and 75%, respectively. Score 3+ MUC1 expression was noted in 60% of N0, 82% of N1 and 100% of N2. Maximum number of cases showing the depth of invasion in subserosa showed the highest score that is Score 3, amounting to 85.71% and Score 3 MUC1 expression was not observed in cases of CRC limited to submucosa. CONCLUSION: MUC1 expression showed a positive correlation with tumor grading, staging, lymph node metastasis, and depth of invasion with more number of cases of poorly differentiated CRC, and higher stages of the tumor showed score 3 MUC1 expression in more cases. Also, cases of CRC showing Lymph node metastasis and depth of invasion in serosa and subserosa showed score 3 MUC1 expression in more cases. These findings suggest a role for MUC1 in the progression of colorectal cancer, suggesting a link of MUC1 expression with the aggressiveness of the tumor and poor prognosis.