Tumour-Associated Tissue Eosinophilia in Oral Squamous Cell Carcinoma- A Boon or a Bane?

Clinical Implications of Tumor‐Associated Tissue Eosinophilia in Tongue Squamous Cell Carcinoma

“…Some studies demonstrated a significant association between high TATE levels and better overall survival . Other studies demonstrated the opposite result, namely, that higher levels of TATE were associated with locoregional recurrence and poorer prognosis . These conflicting results may be explained by inconsistencies in the methods used to measure TATE.…”

“…These conflicting results may be explained by inconsistencies in the methods used to measure TATE. These studies used several different proposals and criteria to classify TATE, and TATE levels varied by the methods used to measure the number of eosinophils, intensity and scores, and location of eosinophils within the tumor . The number of eosinophils per high‐power field and the number of eosinophils/square millimeter (density) are the two most commonly used methods to evaluate TATE .…”

“…Alkhabuli and High demonstrated that the density method was better than the classical method using the distribution of eosinophils in clusters. The current study measured eosinophil counts using the density of TATE in the invasive fronts of tumors from TSCC patients to resolve this inconsistency . The use of the density method and focusing the targeted area on the invasive fronts of tumors consistently provided a spectrum of TATE levels in TSCC tumors, and we used the median value of 61/mm 2 as the cutoff value to stratify our patients into two groups for further analyses.…”

“…These substances are released in the tumor microenvironment and contribute to the loss of cell adhesion, which allows epithelial–mesenchymal transition, promigratory paracrine signaling, endothelial cell proliferation with tumor cell survival, and tumor cell migration . However, these cytokines are potent chemoattractants that recruit eosinophils into the invasive tumor front; these eosinophils release different proteases that produce tissue damage and increase tumor growth and invasion …”

“…Different subsets of leukocytes play distinct roles in the tumor microenvironment, and eosinophils release various proteins that exhibit pro‐ and antitumor immunity . Tumor‐associated tissue eosinophilia (TATE) was defined by Przewoski in 1896 as the intra‐ and peritumoral infiltration of eosinophils, but the role of TATE as a prognostic factor in oral cavity squamous cell carcinoma remains controversial . The heterogeneous classifications or grades proposed in different studies of TATE expression using histopathological examination may contribute to these conflicting results …”