Klin Onkol 2022; 35(Suppl 2): 107-109. DOI: 10.48095/ccko20221S107.
Background: At present, there is no relevant data considering the prevalence and clinical significance of immunohistochemical (IHC) assessment of programmed death ligand-1 (PD-L1) expression in ovarian cancer (OC). Therefore, as a part of our research project of comprehensive profiling of OC, we aimed to analyze PDL1 IHC expression in OC patients treated with platinum-based chemotherapy (P-CT). Materials and methods: The retrospective cohort of 50 patients treated with at least by 6 cycles of primary systemic P-CT at University Hospital Brno in the years 2010–2020 was identified from the clinical database based on predefined criteria. The tumor samples of all involved patients collected before P-CT initiation were IHC analyzed for PD-L1 expression using monoclonal antibody (clone 22C3, Agilent). The slides were scored for TPS (percentage of positive tumor cells) and CPS (combined positive score defined as the number of all positive tumor cells, lymphocytes and macrophages divided by the number of vital tumor cells and multiplied by 100). Results: A total of 25 patients had P-resistant disease (with median platinum-free interval (TFIp) 1 month and overall survival (OS) 10 months) and 25 patients had P-sensitive disease (with TFIp 14 months and OS 51 months in 15 (60 %) patients with recurrence). The stage at diagnosis, histological type and extent of cytoreduction were equally distributed in both cohorts. In the P-resistant cohort, the IHC PD-L1 expression results were as follows: TPS negative in 24 (96%) patients, TPS positive in 1 (4%), CPS < 1 in 13 (52%), CPS 1–10 in 9 (36%) a CPS 10–100 in 3 (12%) patients. The results in the P-sensitive cohort showed negative TPS in 23 (92%), TPS positive in 2 (8%), CPS < 1 in 12 (48%), CPS 1–10 in 7 (28%) and 10–100 in 6 (24%) patients. Conclusion: The results of the extended analyses of the correlation between PD-L1 expression and clinicopathological characteristics will be presented at the conference.
