Abstract 362: Patients with cervical cancer display an increase in leukocytes and myeloid cells that express S100A9

Abstract Cervical cancer is the second most common type of cancer affecting women worldwide. Leukocytosis have been related with treatment failure in this pathology, associated with the induction and accumulation of myeloid derived suppressor cells (MDSC) in peripheral blood. S100A9 proved to be a useful marker to identify MDSC in whole blood from patients with cancer. In this study, we analyzed the number of leukocytes that express S100A9, dividing them according to monocytic (CD14+) or granulocytic (CD15+) myeloid populations in patients with locally advanced cervical cancer (Ptes) and compared to healthy donors (Crls). Methods: Peripheral blood samples collected from 11 Crls and 19 Ptes with cervical cancer (stage IB3-IVA) treated in our Institution between 2018 and 2020 with concurrent chemoradiotherapy (cisplatin) followed by brachytherapy. Blood samples (before treatment, before brachytherapy and post-treatment assessment) were obtained. Leukocytes from buffy coat fraction were isolated and stained for S100A9, CD14 and CD15 and then analyzed by flow cytometry. The predictive value of S100A9+ cells between Ptes and Crls was evaluated and associated with therapeutic response. Results: An increase in leukocytes, granulocytes and monocytes positives for S100A9+ were observed in peripheral blood from Ptes with cervical cancer before treatment compared to Crls. Leukocytes: mean Ptes-Crls: 67.7-48.6; p=0.0017. Granulocytes: mean Ptes-Crls: 62.5-45.9; p=0.0073. Monocytes: median Ptes-Crls: 4.62-2.58; p=0.043. We did not find significant differences in S100A9+ cells over treatment between groups. Tumor response was dichotomized as complete and insufficient response (persistence + progression), relating it to S100A9+ cells. Using a logistic regression model, we observed that the percentage of leukocytes and granulocytes S100A9+ exhibited a trend close to significance of being associated with tumor response [Leukocytes odds ratio (OR): 0.908, 95% confidence interval (CI): 0.819-1.006, p=0.06; Granulocytes OR: 0.907, 95% CI: 0.821-1.002, p=0.057]. In this way, it represents that only a 1% increase in S100A9+ leukocytes or granulocytes are associated with a 9% reduction of having a complete response. Conclusions: In our study, patients with locally advanced cervical cancer presented an increase in total leukocytes and myeloid cells that express S100A9. The relationship that seems to exist between S100A9+ leukocytes and granulocytes with tumor response may suggest that patients with high levels of these circulating cells could defined a higher risk population associated with therapeutic failure. Further analysis and a larger cohort of patients with cervical cancer will be necessary to assess the potential role of S100A9+ leukocytes and myeloid cells as predictive markers. Citation Format: Yanina Veronica Langle, Pablo Damian Cresta Morgado, Denise Belgorosky, Pablo Marenco, Pablo Menéndez, Valeria Cáceres, Andrea Aguilar, Marcela Ostojich, Laura Lay, Ana María Eiján, Eduardo Omar Sandes. Patients with cervical cancer display an increase in leukocytes and myeloid cells that express S100A9 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 362.