Myeloid cell networks govern re-establishment of original immune landscapes in recurrent ovarian cancer

Immunotherapy has produced disappointing results in recurrent ovarian cancer (OC). However, the prognostic value of tumour-infiltrating lymphocytes (TILs) is largely based on the analysis of treatment-naive tumours. To understand the immunobiology of recurrent cancers, and their evolution, we profiled a total of 697 OC tumour samples (566 primary and 131 recurrent including 69 patient-matched samples) from 595 patients of five independent multi-institutional cohorts. By capturing heterogeneous TIL distributions, we identified four immune phenotypes associated with differential prognosis, TILs states and TILs:myeloid networks, which dictate malignant progression after chemotherapy and recurrence. Notably, recurrent tumours recapitulate the immunogenic landscapes of original cancers. Mirroring inflamed human OC, preclinical recurrent Brca1mut tumours maintained activated TILs:dendritic cells (DCs) niches but evaded immune control through COX/PGE2 signaling upregulation. Conversely, recurrent Brca1wt tumours displayed loss of TILs:DCs niches and accumulated immunosuppressive myeloid networks featuring Trem2/ApoEhigh TAMs and Nduf4l2high/Galectin3high malignant states. Our study highlights that persistent immunogenicity in recurrent OC is governed by the BRCA-dependent crosstalk between dissimilar myeloid cells and TILs. We propose new targets to modulate the malignant and TAM compartments which improve efficacy of standard of care chemotherapy in mouse OC models with HR deficiency.

• Type: RNASeq
• Archiver: European Genome-Phenome Archive (EGA)