Immunohistochemical Evaluation of Ki-67 and PTEN Expression in Endometrial Adenocarcinoma: Correlation with Histological Grade and Prognostic Implications
Abstract
Background: Endometrial adenocarcinoma is among the most common gynecologic cancers in the world and with rising incidence which can be attributed to obesity, type 2 diabetes mellitus and lifetime exposure to unopposed estrogen. Traditional prognostic factors (histological grade and FIGO stage) are not sufficient to describe the molecular heterogeneity of this tumor. Ki-67 is a nuclear proliferation biomarker expressed at all active cell-cycle phases and PTEN is the most commonly inactivated tumor suppressor in endometrioid carcinoma, whose joint evaluation could provide better prognostic stratification. Objective: To examine the Ki-67 and PTEN immunohistochemistry in endometrial adenocarcinoma, correlate the expression of both biomarkers with histological grade and test the statistical correlation between the two biomarkers as composite prognostic factors. Materials and Methods: The data was analyzed in terms of grading (by hematoxylin and eosin (H&E) staining) according to WHO 2020s classification and immunohistochemistry (Ki-67 (labeling index scored 0 to 4+, measured in 5 high-power fields) and PTEN (immunoreactive score 0 to 9: absent, low, moderate, or high) of 50 formalin-fixed paraffin-embedded (FFPE) endometrial adenocarc Chi-square test and Spearman rank correlation coefficient (significance level: p < 0.05) were used to evaluate the statistical associations. Results: The high level of Ki-67 (>51%), moderate level (12), and low level of Ki-67 (8) were observed in 30 cases (60%), 12 cases, and 8 cases respectively. In 25 cases (50%), PTEN was absent altogether (25); in 15 cases (30%), it was low, in 8 cases (16%), it was moderate, and in 2 cases only (4%), it was high. Cross-tabulation showed that complete PTEN loss was seen in 66.7% of high-Ki-67. An important negative correlation was established between the two markers ( 2 = 17.91, 6df = 6, p = 0.0065; Spearman 0467, p = 0.0006). Download Full Text