EVALUATION OF THE OPTIMAL KI-67 CUTOFF VALUE DETERMINING GRADES OF GLIOMA IN TURKISH POPULATION
Gliomas are a heterogenous group of malignancies, occupying nearly 80% of central nervous system (CNS) primary malignant tumors and rank the first among brain tumors. The Ki-67 is a routinely assessed protein in the pathological study of a tumor. It’s widely investigated as a proliferation marker throughout the literature for its prognostic, predictive and therapeutic roles. A local Turkish cohort of 102 patient in the Medical Park/ Goztepe, Bahcesehir university, were enrolled in this retrospective study, to identify a precise cut point of ki-67 protein level, separates between glioma WHO assigned grades, and to explore the possible predictive relationship between Ki-67 proliferation index and the preoperatively levels of differential white blood cells in series of archival adult malignant gliomas with grade II, III and IV lesions. The statistical tests revealed that ki-67 expression level of 9.5% is a significant cutoff value between grade IV Glioblastoma and grade II and III astrocytic and oligodendroglia gliomas. And according to the findings, Age and preoperatively measured Monocyte’s count showed a statistical difference between patients with low (<10%) and high (≥10%) expression of ki-67. Thereby, result reinforces the statement that Ki-67 is in proportion to the glioma histologic malignancy degree and is a good tool for assigning grading between GBM and non-GBM gliomas. Hence, encouraging that ki-67 is a potent candidate in development of new classification system combining morphological, molecular and genetic features to better diagnose and treat glial malignant tumors.
Keywords: Ki-67, Grading, GBM, Glioma, Cutoff, Turkey