Primary adenocarcinoma of colon: A clinicopathological study with the prevalence and correlation of CDX2 biomarker expression - A tertiary care center experience

Background: Colorectal cancer is one of the alarming health problems worldwide. Prognostic biomarkers are the key for risk stratification in patients with colon cancer and the decision to recommend adjuvant chemotherapy. It has been difficult to identify a single prognostic biomarker for colon cancer. Currently, tumor stage, tumor grade, and microsatellite instability remain the most important prognostic variables that aid in the treatment of patients with colon cancer. Some studies highlighted that CDX2 immunohistochemistry negativity is an independent prognostic factor and indicates a worse survival rate. Our aim was to study the prevalence of CDX2 biomarker expression in patients diagnosed with primary adenocarcinoma and to correlate this with the clinical profile and pathological features. Methods: Endoscopic mucosal biopsies and resection specimens of 148 patients diagnosed with colonic adenocarcinoma were analyzed. CDX2 immunohistochemistry was performed, and the result was correlated with clinicopathological features. The results were presented as mean, frequencies, and percentages. Pearson's Chi-square test was used to assess the associations between clinicopathological parameters and CDX2 immunohistochemistry negativity. Results: The prevalence of CDX2 expression by immunohistochemistry in colon cancer was found to be 92%. CDX2 biomarker negativity was found to be higher in left-sided colon cancers, poorly differentiated adenocarcinoma, mucinous carcinoma, and higher TNM stages. Conclusion: CDX2-negative tumors are often associated with several adverse prognostic variables (e.g., advanced stage, poor differentiation, and metastasis). Thus, sub-classification of colon cancer based on the CDX2 biomarker aids to separate them into prognostically relevant categories.