Ki-67 proliferating index and histological grade, type and stage of colorectal carcinoma.

BACKGROUND The objective of this study was to assess the relationship of histological type, grade and stage of colorectal carcinoma with proliferative activity as measured by Ki-67 LI. It was a descriptive study and conducted at the Department of Pathology, University of Health Sciences, Lahore. METHODS Ki-67 is a protein associated with cell proliferation and is expressed in all the phases of cell cycle except G0. In the present study, Ki-67 expression in 50 patients with colorectal adenocarcinomas was observed using immunohistochemistry with monoclonal antibody MIB-1. RESULTS Ki-67 LI was high in well and moderately differentiated adenocarcinomas (mean Ki-67 LI 392.50 +/- 56.58 and 342.24 +/- 96.84 respectively) as compared to poorly differentiated adenocarcinomas (mean Ki-67 LI 250.00 +/- 113.46). Ki-67 LI was high in non mucinous adenocarcinomas than mucin secreting and signet ring cell adenocarcinomas (mean Ki-67 393.93 +/- 55.91 vs 220.00 +/- 49.72 and 200.00 +/- 79.05 respectively). As regard the Dukes' staging, Ki-67 LI was high in colorectal carcinomas in Dukes' stage B than tumours in Dukes' stage C (Mean Ki-67 LI 360.13 +/- 90.03 vs 241.66 +/- 101.31 respectively). CONCLUSION The proliferative activity as measured by Ki-67 antibody is related to histological type, grade and stage.