Tumor Associated Tissue Eosinophilia As a Potential Predictor in the Invasion Patterns of Oral Squamous Cell Carcinoma

Background: Eosinophils are a rare type of granular leukocyte comprising only 1-4% of the total white blood count. Their presence within a wide variety of human cancers raises queries about their role. The pattern of invasion (POI) in oral squamous cell carcinoma (OSCC) has been recognized as an adverse prognostic feature. Different theories have been proposed linking tumor-associated tissue eosinophilia (TATE) and its role in tumor progression. Hence, this study aims to assess the role of TATE in the invasion pattern of OSCC. Materials and Methods: It is a cross-sectional study of a retrospectively collected 70 cases of OSCC, drafted from the institutional archive (2011-2014). The archival paraffin-embedded tissues were retrieved and subjected to sectioning and staining with hematoxylin and eosin and carbol chromotrope (Lendrum, 1944). The TATE was graded based on modified classical counting method (Alkhabuli and High, 2006), and the POI was evaluated based on Bryne's invasive tumor front grading system (1989). Chi-square test (P < 0.05) was employed to assess the relationship between the selected parameters. Results: Statistically significant association was found between TATE count at the invasive front and POI (P < 0.001), histological grading (P < 0.002), and the TATE count at the noninvasive front (intra- and stroma subadjacent to surface epithelium) (P < 0.010). patient demographics and nodal metastases correlation with TATE count resulted in insignificant statistical association. Conclusion: Thus, the positive correlation between TATE and POI suggests that the eosinophils might play a role in tumor- cytotoxicity and affect tumor growth.