Clinicopathological Study of CK19 Expression in Head and Neck Squamous Cell Carcinoma and Its Association with Tumor Grading: A Cross-Sectional Study.

Abstract

Introduction: Head and neck squamous cell carcinoma (HNSCC) is a histologically heterogeneous group of tumors with diverse biological behavior. Cytokeratin 19 (CK19), part of the epithelial cytoskeletal network, may indicate tumor differentiation and progression. This cross-sectional study evaluated CK19 immunohistochemical expression in HNSCC and its correlation with histological grade using two grading systems. Materials and Methods: A cross-sectional study of 100 biopsy-confirmed HNSCC cases was conducted at the Department of Pathology, Pt. B.D. Sharma PGIMS, Rohtak. Tumors were graded using the WHO system and Anneroth's six-parameter system. CK19 expression was assessed by immunohistochemistry and scored 0-3 based on the percentage of stained tumor cells. Chi-square and Fisher's exact tests were used for statistical analysis. Results: Patients ranged from 28-86 years (mean 57.16 ± 11.70 years) with a male predominance (88% male, 12% female). CK19 expression was positive in 69% of cases, rising with tumor grade: 41.4% in well-differentiated, 78.3% in moderately differentiated, and 84% in poorly differentiated carcinomas (p < 0.001). Anneroth grading also showed a rising trend, though with inconsistencies in grade II/III classification. The highest CK19 expression (score 3) predominated in Anneroth grade III/IV tumors. Conclusion: CK19 expression is significantly associated with poor tumor differentiation in HNSCC, particularly by WHO grading, supporting its potential as a prognostic biomarker that may enhance grading accuracy and inform treatment strategies. Recommendation: CK19 immunohistochemistry should be considered an adjunct to routine histopathological grading in HNSCC, with larger, standardized, multicentric studies recommended to validate its prognostic reliability.