Abstract 3647: Digital spatial transcriptomic reveals different epithelial and immune cells signatures across endometriosis-related diseases: From simple ovarian endometriosis to ovarian cancer

Abstract Endometriosis represents a pressing medical concern, imposing a relevant burden on patients including potential malignant transformation into endometriosis-associated ovarian cancer (EAOC). Despite the process of cancer development remains unclear, immune cells abnormalities arose as putative biomarkers in the neoplastic progression. One-third of ovarian endometriosis cases exhibit PD-1/PD-L1 expression levels comparable to those observed in cancer. To substantiate the biological basis of these findings, this study aimed to elucidate the spatial transcriptomic profile of epithelial and immune components from different endometriosis-related conditions, along with their genetic interplay. Formalin-fixed paraffine embedded (FFPE) specimens from 4 ovarian endometriosis (OE) cases, two of which displayed elevated levels of PD-1/PD-L1 expression and were referred to as cancer-like endometriosis (CLE), 1 Clear Cell Ovarian Cancer (CCOC) and 1 Endometrioid Ovarian Cancer (EOC) were cut in 5um section for spatial transcriptomic analysis using GeoMX Human Whole Transcriptome Atlas (WTA) probe-set (18000 genes). For all sections, the regions of interest (ROIs) were identified using a set of morphology markers: anti-human CD3, CD68 and PanCK antibodies. Spatial transcriptomic analysis revealed condition-specific gene enrichment of epithelial and immune cells across the different conditions. In spite of similar H Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 3647.