A METHOD FOR DIGITAL QUANTIFICATION OF EOSINOPHILS INFILTRATE IN ORAL SQUAMOUS CELL CARCINOMA

Abstract

Introduction:The recent advances in tumor immunotherapy triggered more attention towards analysis of tumor inflammation. Oral squamous cell carcinoma (OSCC) is malignancy that can be therapeutically challenging and resistant to treatment. Further investigation of the inflammatory profile in OSCC can enhance our understanding of the disease and hence patient response to immunotherapy. Eosinophils are suggested to play a significant role in tumor progression and have been described to be associated with advanced stage malignancies of several tumor subtypes. Objective: Here we wanted to assess a methodology to quantitatively measure eosinophils infiltrate in OSCC. Material and methods: Eosinophils infiltrate was analyzed in formalin fixed paraffin embedded tissue (FFPE) microarray cores of 30 oral squamous cell carcinomas (OSCC), and 10 normal oral epithelium controls. Digital analysis using the auto fluorescence of eosinophils accentuated by Alexa Fluor 488 stain, in FFPE tissue sections; we used Cytation 5 machine and Gen 5 software, to digitally quantify the extent of eosinophils infiltrate in OSCC. Results: Out of the inflamed OSCC examined sections with heavy inflammatory infiltrate rich in eosinophils, RBCs, neutrophils and monocytes, eosinophils were readily detected, and digitally quantified after staining with Alexa Fluor 488. The tumor cores showed eosinophils infiltrate in the peri-tumoral stroma of 26 (87%) of the 30 examined OSCC Conclusion: This study highlights the importance of assessment of the type and extent of inflammatory cells infiltrate as well as its digital quantification. It provides a novel quantification method of eosinophils that opens avenues to study the correlation between eosinophils infiltrate and tumor prognosis.