Role of Ki-67, Cyclin D1, and p53 in Early Diagnosis and in the Prognosis of Oral Squamous Cell Carcinoma: A Cross-sectional Study Research Protocol

Introduction: Oral Squamous Cell Carcinoma (OSCC) accounts for more than 90% of all oral cancers. It is among the top three cancers in India, along with cervical and breast cancer. Oral Epithelial Dysplasia (OED) represents a premalignant lesion that can evolve into OSCC. Early detection of OED and prediction of OSCC prognosis remain a major challenge in clinical practice. Molecular markers have emerged as promising adjuncts to histopathology in the assessment of OED and OSCC. Need of the study: Histopathological grading is the most widely used method for assessing OED and OSCC. Despite updated grading systems, histology often fails to reliably predict malignant progression and clinical outcomes. A delay in diagnosis affects survival rates, underscoring the need for additional laboratory tools for early detection and prognosis. Immunohistochemistry (IHC) biomarkers such as Ki-67, Cyclin D1, and p53 have shown individual promise in several studies. On the other hand, studies on their combined use remain limited. This study aims to investigate the combined potential of these three biomarkers in early diagnosis and prognosis across the full histological spectrum of OED and OSCC. Aim: To correlate the expression levels of Ki-67, Cyclin D1, and p53 with the histopathological grades of OED and OSCC and to demonstrate their utility in early diagnosis and prognosis. Materials and Methods: A single-centre prospective cross-sectional study will be conducted between July 2025 and May 2026 at the Department of Pathology, Jawaharlal Nehru Medical College, DMIHER, Sawangi (Meghe), Wardha, Maharashtra, India. The target sample is planned to consist of 61 cases (30 OED, 31 OSCC), with a projected dropout rate of 10% to provide at least 55 analysable cases. According to the “World Health Organisation WHO 5th edition (2022)” criteria, OED will be classified as mild, moderate, or severe, and OSCC as Well Differentiated (WD), Moderately Differentiated (MD), or Poorly Differentiated (PD). IHC will be performed using validated antibody clones. The scoring will assess the labelling index (LI %) for Ki-67 and p53, the Immunoreactivity Score (IRS) for Cyclin D1, and layer-specific expression patterns. Inter-observer agreement will be assessed. Spearman’s rho (ρ) correlation coefficient will be employed to determine the association between biomarker expression scores and OED/OSCC histopathological grade progression. A p-value of less than 0.05 will be regarded as statistically significant.