Ki67 immunoexpression in different histological grades of Oral squamous cell carcinoma: a retrospective study

Oral squamous cell carcinoma (OSCC) accounts for over 90% of all oral malignancies and has a 50-60% five-year survival rate, despite advances in treatment. Ki67, a nuclear protein involved in cellular proliferation, has been studied as a prognostic marker in various malignancies, including OSCC. However, its link with different histological grades of OSCC is uncertain. The study aimed to evaluate Ki-67 expression in well-differentiated (WDOSCC), moderately differentiated (MDOSCC), and poorly differentiated (PDOSCC) tumors to ascertain its correlation with tumor differentiation and aggressiveness. Forty OSCC cases were classified using Broder's histological grading system. Ki67 immunohistochemical staining was performed, and three groups were categorized based on Ki67 expression: low (1-25%), moderate (26-50%), and high ( > 50%) proliferation. Statistical analysis assessed the significance of Ki67 expression across OSCC grades. Among 40 cases, 35% were WDOSCC, 45% MDOSCC, and 20% PDOSCC. Low Ki67 proliferation was seen in 64% of WDOSCC, moderate in 61% of MDOSCC, and high in 75% of PDOSCC. There was a significant (<i>p</i> < 0.001) association between OSCC grading and Ki67 expression. Ki67 expression correlates with OSCC histological grades, increasing with tumor proliferation. These findings support Ki67 as a prognostic marker, warranting further large-scale validation studies.