Correlation of cyclin D1 expression with aggressive DNA pattern in patients with tobacco-related intraoral squamous cell carcinoma

BACKGROUND & OBJECTIVES Cyclin D1 has been strongly implicated in cell proliferation particularly in the G1/S checkpoint of the cell cycle, and prognoses in human malignancies. We investigated the correlation between cyclin D1 overexpression and clinicopathological features as well as cell cycle parameters to understand its clinical significance in patients with tobacco-related oral squamous cell carcinoma (OSCC). METHODS Immunohistochemistry for cyclin D1 and DNA flowcytometry for cell cycle parameters was done on paraffin embedded tumour samples from 45 patients with OSCC RESULTS: Higher expression of cyclin D1 was observed only in 30 (66.6%) of 45 cases that correlated with advanced age (P <0.02), higher tumour stage (P<0.01), histological differentiation and lymph node metastasis (P <0.01). Analysis of nuclear DNA pattern revealed cyclin D1 immunoreactivity in tumours with aggressive DNA pattern such as aneuploidy (P<0.05) and higher S phase fraction (P<0.04). INTERPRETATION & CONCLUSIONS Higher expression of cyclin D1 in oral cancer appears to be closely linked to cell proliferation, differentiation and lymph node invasion. Pre-operative evaluation of cyclin D1 in biopsy specimen may be useful in planning the most appropriate treatment strategies in patients with tobacco-related OSCC.