Abstract
Oral Cavity Squamous Cell Carcinoma (OSCC) ranks 6th most common cancer across the world. Cyclin D1 regulates G1 to S phase of cell cycle. Its uncontrolled expression leads to excessive cell proliferation and neoplasia. This makes Cyclin D1 a possible biomarker for early diagnosis and management strategies. Fifty oral cavity histopathology specimens (10 benign lesions and 40 OSCC) were evaluated in a teaching hospital. Cyclin D1 expression was studied. Statistical significance (p value of ≥ 0.05 were considered insignificant) was calculated by Chi-Square and Mann-Whitney Wilcoxon test. We observed 15 well-differentiated Squamous cell carcinomas (WDSCC), 15 moderately-differentiated squamous cell carcinomas (MDSCC), 10 poorly-differentiated squamous cell carcinomas (PDSCC) amongst our cases of OSCC. Common sites were buccal mucosa (47.5%), tongue (35%) and tonsillar area (5%). All OSCC showed positivity for cyclin D1; while benign lesions exhibited immunoreactivity to cyclin D1 with mild staining of only < 10% cells. High Labeling Index (score 4) was seen more in PDSCC (70%) as compared to MDSCC (6.6%), WDSCC (00%). PDSCC showed strong intensity in 80% cases while only 20% MDSCC and 0% WDSCC cases had strong staining. Increase in Cyclin D1 immuno-reactivity is associated with decrease in cell-differentiation. Cyclin D1 may be a target for molecular based therapy leading to improved prognosis in OSCC.