IL-17–Driven Tumor Cell–Intrinsic Inflammatory Programming Creates an Immunotherapy-Permissive Microenvironment [scRNA-Seq]

Across large clinical cohorts, an IL17A^high subset demonstrated a T cell–inflamed gene expression profile independent of microsatellite instability and tumor mutational burden; however, this phenotype was not associated with survival in untreated disease. Mechanistically, IL-17 directly activated NF-κB–dependent inflammatory programs in OCCC tumor cells, inducing cytokines involved in T-cell recruitment and activation.

In vivo, IL-17 remodeled the immune microenvironment, increasing infiltration and activation of both CD4⁺ and CD8⁺ T cells. Single-cell profiling further revealed expansion of Th17/Tfh-like CD4⁺ T cells and cytotoxic, non-terminally exhausted CD8⁺ T cells. Consistent with these findings, anti–PD-L1 therapy significantly improved survival exclusively in Th17-biased partial chimera mice.

Collectively, these results demonstrate that a Th17-biased, IL-17–responsive immune contexture in OCCC engages tumor cell–intrinsic NF-κB inflammatory signaling to prime antitumor T-cell states and enable checkpoint blockade efficacy. This immune biology is predictive rather than prognostic, supporting a biomarker-driven immunotherapy strategy for OCCC within otherwise ICI-refractory ovarian cancer.