Expression of CDX-2 and Ki-67 in different grades of colorectal adenocarcinomas.

ABSTRACT

Background: CDX2 is a caudal homeobox gene essential for intestinal differentiation and is specifi cally expressed in colorectal adenocarcinomas. Its role in colorectal carcinogenesis is not fully elucidated. Aims and Objectives: To study the expression pattern of CDX2 and Ki-67 in different grades of colorectal adenocarcinomas and to observe the relationship of their staining patterns in various tumor stages and to look for correlation if any, between Ki-67 labeling index (Ki-67 LI) and CDX2 expression. Materials and Methods: A total of 74 cases were enrolled. Detailed clinical profi le, peroperative fi ndings, histological grading and staging were noted. Immunohistochemistry for CDX2 and Ki-67 was done, and Ki-67 LI was calculated. CDX2 staining was graded semiquantitatively, and statistical analysis was done. Result: Age of presentation ranged from 20 to 75 years, and the malefemale ratio was 1.831. There were 8, 47 and 13 cases of well, moderate and poorly differentiated adenocarcinomas, respectively. The mean Ki-67 LI of well, moderate and poorly differentiated adenocarcinomas were 14.25, 31.34 and 43.08 respectively, and their difference was statistically signifi cant, correlation was also noted with stage. CDX2 expression appeared to be stronger in poorly differentiated cases, but there was no signifi cant difference in its expression in the different grades and stages. There was no correlation between Ki-67 LI and CDX2 immunostaining pattern. The lymph node metastasis showed CDX2 positivity in all the cases. Conclusion: Expression of CDX2 does not signifi cantly change with the grade of colorectal adenocarcinomas. However, it is an important diagnostic marker in metastatic colonic lesions. The Ki-67 LI, on the other hand, showed a strong correlation with histopathological grades.