An Immunohistochemical Study of HIF-1 Alpha in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

To evaluate and compare the expression of HIF-1 Alpha (HIF-1α) in oral epithelial dysplasia (OED) and various grades of Oral squamous cell carcinoma (OSCC). 30 cases each of OEDand OSCC were stained with HIF-1α antibody. Quantification of HIF-1α positive cellswas carried out and the data was statistically analysed. The mean % HIF-1α labeling index (HIF-1α LI) increased significantly from mild OED (32.11%), moderate OED (55.07%), to severe OED (64.58%). There was a statistically significant increase in the expression of HIF-1α as grades of OED increased. The mean HIF-1α LI % in well differentiated OSCC was 46.3%, Moderately differentiated OSCC—76.31% and Poorly differentiated OSCC—89.9%. The mean HIF-1α LI was found to increase with increasing grades of OSCC which was statistically significant (P < 0.05). Further a comparison of mean HIF-1α LI in OED with different histologic grades of OSCC by Independent samples t test was performed. We found statistically significant difference between OED and moderately differentiated OSCC and OED and poorly differentiated OSCC (P = 0.000). Progressive increase in expression of HIF-1α was noted from OED to OSCC. It can be postulated that epithelial dysplastic lesions with increased HIF-1α expression are at greater risk of malignant transformation, suggesting that the expression of HIF-1α is an early event in oral carcinogenesis.