Single-cell transcriptomic analysis reveals intra-tumoral heterogeneity and immunotherapy strategies in high-grade serous ovarian cancer.

High-grade serous ovarian cancer (HGSOC) is the most common type of ovarian cancer, characterized by high intra-tumoral heterogeneity and platinum resistance. In this study, single-cell RNA sequencing data with HGSOC were analyzed. We identified seven major cell types in HGSOC and observed significant changes in the proportions of cancer-associated fibroblasts and epithelial cells as tumor drug resistance increased. The abundance of IFIT1 (+) and CXCL10 (+) epithelial cells highly expressing MHC class â molecules, which are strongly associated with antigen processing and presentation, was found to improve patients' outcomes. Ultimately, the relationships between IFIT1, MHC class â molecules, and CD8(+) T cells were verified in additional cohorts, using multiplex immunohistochemistry. Our data suggest that IFIT1 (+) epithelial cells might enhance immune surveillance via increasing the expression of MHC class â molecules and activating CD8(+) T cells. Our findings provide a valuable resource for deciphering intra-tumoral heterogeneity and mechanisms driving the aggressiveness of HGSOC, revealing potential biomarkers for anti-cancer treatment.