Histopathological and Immunohistochemical Evaluation of CDX2 and Ki67 in Colorectal Lesions with their Expression Pattern in Different Histologic Variants, Grade, and Stage of Colorectal Carcinomas

BACKGROUND: A variety of colorectal lesions are surgically treated encompassing both benign and malignant polyps and colorectal cancer (CRC). CRC is the third most common cause of death in developed countries. Over the last decade, CDX2 has been linked to CRC progression, with reduced expression of the protein associated with more advanced tumor stage, vessel invasion, and metastasis. AIMS AND OBJECTIVES: To analyze the histopathology and immunohistochemistry (IHC) of CDX2 and Ki67 with their expression pattern; in different lesions of colon and rectum with special reference to various grade/stage/histological variants of CRC and to find out whether they can be used as possible predictive marker. MATERIALS AND METHODS: The study conducted was hospital based, both retrospective and perspective type comprising colorectal samples of total 367 cases (N) within a period of 2½ years. Surgical samples were collected, then grossed, processed, stained with routine hematoxylin and eosin stain in our department followed by IHC of CDX2 and Ki67 in only 60 randomly selected cases (n = 60). RESULTS: Out of total 367 cases, 265 cases were prospective study and 102 cases were retrospective study (240 cases were colonic lesions, and 127 are rectal lesions). The samples included were both from colonoscopy biopsy (small) 319 cases and 48 colectomy specimen (large). Mean age of the study participants was 49.62 years with a standard deviation of 17.34 years and predominantly male, but the difference was not statistically significant (P > 0.05). Colon (238 cases, 64.9%) as a whole affected more than rectum and left sided tumors more than the right side. All 60 cases were found to be positive for CDX2 expression (i.e., 100%); majority (n = 38) being carcinoma cases possessing high score and was statistically significant (P = 0.008, using Chi-square test) indicating strong association, whereas Ki-67 showed an increased index from noneoplastic to neoplastic cases. CONCLUSION: These markers can be used as future predictive biomarkers which will precisely evaluate risk group, prognosis, and response to therapy hence can be used as target therapy reducing irrational treatment.