Barzilai University Medical Center

79 Research Day 2020 Barzilai University Medical Center 56 THE ORAL MICROBIOME AS A DIAGNOSTIC TOOL IN MALIGNANT AND PREMALIGNANT LESIONS OF THE ORAL CAVITY, PRELIMINARY RESULTS Irit Allon 1,5 , Oded Nahlieli 2,5 , Michael Abba 2 , Milena Piteshny 3 , Alejandro Livoff 1 , Shlomo Maayan 4,5 1 Institute of Pathology, Barzilai University Medical Center, Ashkelon, Israel 2 Department of Oral & Maxillofacial Surgery, Barzilai University Medical Center, Ashkelon, Israel 3 Microbiome research unit, Rambam Medical Center, Haifa, Israel 4 Division of Infectious diseases, Barzilai University Medical Center, Ashkelon, Israel Faculty of Health Studies, Ben Gurion University of the Negev, Beer Sheva, Israel Background Oral squamous cell carcinoma (OSCC) is the most common malignant neoplasm of the oral cavity and the fourth leading malignancy and cause of cancer-related death in the male population. Most cases are preceded by premalignant lesions that present as white, red or combined lesions. The overall prognosis has not improved in the last decade and stands on a mean 5 years survival of 50%. Therefore, improved detection of early oral health disorders is indispensable. The involvement of oral bacteria in inflammation and their association with OSCC provide a feasible target for diagnosis. Hypothesis The composition of the oral microbiome will reveal significant differences between premalignant lesions and cancer patients and will differ from the controls. These composition changes might have the potential to constitute a biomarker for monitoring the oral carcinogenesis transition from epithelial precursor lesion to cancer. Objectives The objectives of this study were to characterize the microbiome of oral premalignant lesions and OSCC and to compare them to non- neoplastic controls. Results Faith-phylogenetic diversity showed a significant difference in diversity between normal controls (NC) versus premalignant lesions (OED), and normal controls versus OSCC groups (q value). It appears that distances between samples within a group are more similar to each other then they are to samples from the other groups and that premalignant lesions (OED) and OSCC are significantly different from normal controls (NC). Conclusion The study is still ongoing and patients are still being recruited. In the next stage, differential abundance between groups should be calculated and longitudinal samples analyzed. However, according to the preliminary results, premalignant and malignant lesions are significantly different from normal controls. This points that the oral microbiome bears the potential to serve as a diagnostic tool in the diagnosis of oral premalignant and malignant lesions.