MGMT Immunohistochemical Expression in Colorectal Carcinoma and its Correlation with Tumor Progression

Abstract

Introduction: There is an urgent need to identify predictive features and markers for colorectal carcinoma (CRC) progression and treatment. This study aimed to assess O6-methylguanine DNA methyltransferase (MGMT) expression in CRC and correlate with the clinico-pathological aspects of the tumor, also to evaluate the relationship between different histopathologic parameters and tumor progression.
 Material and Methods: The study was carried on 70 colectomy using formalin fixed paraffin embedded tumor tissue. Immunohistochemistry was used to detect MGMT expression, and clinico-pathologic aspects as well as Tumor budding, type of desmoplastic reaction, inflammatory lymphocytic milieu, pattern of invasive front and necrosis were assessed Then correlated with MGMT expression and tumor progression, using parametric and nonparametric statistical methods.
 Results: MGMT Loss of expression was detected in 42.9% of CRC cases. MGMT expression status was significantly correlated with tumor stage and metastatic status (p<0.05), while it was not correlated with other clinic-pathologic features, (p>0.05). Desmoplastic reaction (DR), tumor budding, stromal tumor infiltrating lymphocytes (TIL-S) and necrosis were correlated with tumor stage (p<0.05). DR correlated with tumor budding (p<0.05). Both types of TIL and Crohn’s-like lymphoid reaction (CLR) showed a mutual correlation (p<0.05).
 Conclusion: MGMT high expression and histopathologic parameters as DR, tumor budding, inflammatory lymphocytic milieu and necrosis could be correlated with CRC progression.