Ki-67 Expression as a Predictive Factor of Muscle Invasion in Bladder Cancer

BACKGROUND Bladder cancer is the 9th most frequent cancer worldwide. Ki-67 is immunohistochemistry marker that is predictive of cancer cell proliferation. The expression of Ki-67 is associated with poor prognosis in several types of malignancy, yet the value of Ki-67 as the prognostic factor in bladder cancer remains controversial. AIM This study is aimed to investigate the association between Ki-67 expression with muscle-invasive bladder cancer (MIBC) and non-muscle invasive bladder cancer (NMIBC). METHODS This was a case-control study with a retrospective design. The study was conducted at the Department of Pathology, University of Sumatera Utara, Indonesia. Samples were paraffin blocks from patients diagnosed with bladder cancer and agreed to be put in the study. The samples were stained with Immunohistochemistry Staining (IHC), and then we quantitatively counted the number of the Ki-67 stained nucleus on a microscope. RESULTS A total of 54 samples were obtained in this study. Samples consisted of 27 samples with NMIBC and 27 samples with MIBC. The cut-off point was 20%, we found 17 patients with MIBC and 14 patients with NMIBC presented with biomarker > 20%. Biomarker ≤ 20% was found in 10 patients with MIBC and 13 patients with NMIBC. On statistical analysis with Chi-Square test, no significant association found (p = 0.583) between KI-67 and muscle - invasiveness with OR of 1.579, 95% CI (0.533-4.678). CONCLUSION There is no association between expression of Ki-67 and muscle invasiveness in bladder cancer.