Expression of Cyclin D1 in Normal Oral Mucosa, Epithelial Dysplasia and Oral Squamous Cell Carcinoma

BACKGROUND: Cyclin D1 (also known as PRAD1) is a protooncogene that responds to extracellular mitogens and is a regulator of of G1 phase progression through the cell cycle. The most commonly reported alteration of Cyclin D1 is gene amplification (11q13) resulting in overexpression of a structurally normal protein, but at abnormally high levels, which leads the cell to a state of uncontrolled proliferation. Conventional treatment modalities do not completely eliminate the risk of malignant transformation and therefore it is important to develop objective prognostic markers which will identify high risk lesions. AIMS AND OBJECTIVES: To evaluate and correlate the immunohistochemical expression of Cyclin D1 in Oral epithelial dysplasia, oral squamous cell carcinoma and normal mucosa. MATERIALS AND METHODS: This is an inter observational study including a total of 70 samples (30 oral epithelial dysplasia, 30 squamous cell carcinoma and 10 normal mucosa). Immunohistochemical expression of Cyclin D1 was analysed in formalin fixed paraffin fixed embedded blocks of histopathologically confirmed cases using Cyclin D1 antibody. Counting of positive cells was done on all slides and the mean labelling index was obtained and statistically analysed. RESULTS: There was a significant variation in the expression of Cyclin D1 between the samples of oral epithelial dysplasia, oral squamous cell carcinoma and normal mucosa. The expression of Cyclin D1 is lowest in normal mucosa, followed by oral epithelial dysplasia and the highest expression is seen in oral squamous cell carcinoma. Oral squamous cell carcinoma shows the highest positivity of (64%) and oral epithelial dysplasia showing (44%) positivity and the least positivity is seen in normal mucosa (20%), there by concluding that there is overexpression of Cyclin D1 in Oral squamous cell carcinoma. CONCLUSION: The observation from the present study suggest that Cyclin D1 may be considered as a marker in assessing the risk of malignant transformation of oral epithelial dysplasia and prognosis of oral squamous cell carcinoma. Further studies with larger sample size and proper follow up are recommended.