Quantitative Evaluation of Tumour - Associated Tissue Eosinophilia and Cyclo-oxegenase-2 Gene in Oral Cancer Patients with Assessment of Long Term Outcomes

Various histopathological parameters have been extensively studied for prognostication of oral cancer but the focus is now getting diverted towards the role of inflammatory mediators in cancer progression. The present study was undertaken to evaluate two such components of the inflammatory milieu, tumor-associated tissue eosinophilia (TATE) as well as Cyclo-oxygenase-2 (COX-2) gene expression, quantitatively in oral squamous cell carcinoma (OSCC) patients in relation to treatment outcomes and patterns of recurrence. A total of forty five patients with primary OSCC matching our inclusion criteria were selected for the study and followed up over a five year period. TATE was evaluated from the invasive front of the tumor using Haematoxylin and eosin (H & E) stained sections of histopathological specimens and graded as mild, moderate or intense. COX-2 gene expression was obtained from specimens using the reverse transcriptase - polymerase chain reaction (RT-PCR) method. A statistically significant association was observed between degree of TATE and locoregional recurrence (P < 0.001). The expression of COX-2 gene ranged from 0.4326 to 0.9998 and a higher mean COX-2 score was recorded in samples with intense degree of TATE followed by moderate and mild TATE. (P < 0.001). Using the t-test, the difference in mean COX-2 was found to be statistically significant (P < 0.001) between patients who developed locoregional recurrence and those who did not. The analysis of TATE may provide an indication of future recurrence at the time of diagnosis of OSCC. Also, the increased expression of COX-2 gene in OSCC strongly suggests its possible use as a chemopreventive/chemotherapeutic target.