Tumor budding in colorectal adenocarcinoma using cytokeratin 20 immunostaining

Introduction: Colorectal cancer is the third most common cancer worldwide and second most common fatal cancer. Tumor budding is an emerging prognostic indicator in cancers. Though tumor budding can be assessed using Hematoxylin and Eosin stain, sometimes peritumoral inflammation and reactive stromal fibrosis obscures the tumor buds. The present study aimed to assess tumor budding using cytokeratin 20 immunohistochemistry in colorectal cancers. Methods: This is a cross sectional study which included 30 cases of colorectal carcinomas. cytokeratin 20 stained slides of colorectal carcinoma were assesed for tumor budding using International Tumor Budding Consensus Conference (ITBCC) 2016 consensus criteria and compared with AJCC cancer stage. Results: Demographic analysis showed peak incidence of colorectal cancer in the age group of 55-64 years (33.3%) and male: female ratio of 1.14:1. Majority of the tumors with score 1(23.3%) showed stage I. While tumors with score 2 had similar incidence of stage I (16.6%) and II (16.6%) and lesser incidence of stage III (3.33%). Most of the tumors with score 3 tumor budding had stage III tumors (26.67%). The p value is < 0.0001, which is statistically significant. Tumor budding signifies the biological and molecular phenomenon of epithelial-mesenchymal transition in the tumor microenvironment. Loss of E-cadherin, alterations in transcription factors including SNAIL, ZEB, TWIST etc and switching of CMS2 to CMS4 are some of the recorded molecular profiles responsible for tumor budding. Conclusion: This study concludes that the tumor stage increases with tumor budding and thus is a reliable marker in predicting the prognosis. This study also states that immunohistochemical study gives objective scoring of tumor buds in colorectal cancers. Keywords: tumor budding; colorectal cancer; cytokeratin 20; prognostic marker