OveRcoming immunosupprEssion aNd rebAlancing the Immune reSponSe in ovAriaN CancEr Study

Bone marrow samples (40 ml) will be obtained from the sternum or the iliac crest according to standard practice by experienced operators during the surgery patients will undergo as part of their medical treatment. BM mononuclear cells will be isolated using Ficoll-Paque and progenitor cells will be enriched using positive selection with CD34 beads by MACS. Progenitor cell composition will be identified using flow cytometry. HSPC proliferation assays (standard CFU assays) to assess myeloid colony-forming potential will be performed. In addition, single-cell RNA- sequencing and epigenetic assessment (ATAC-seq, ChIP-seq, DNA methylation) will be performed.

Whole blood (60 ml) will be collected and peripheral blood mononuclear cells (PBMC) will be isolated using Ficoll-Paque. Cellular subpopulations will be purified using negative selection of monocytes with PanMonocyte beads by MACS.

Peritoneal fluid will be collected during the surgery.

Spleen samples will be obtained by experienced surgeons during the debulking surgery. Spleen mononuclear cells will be isolated using Ficoll-Paque and progenitor cells will be enriched using positive selection with CD34 beads by MACS. Cellular subpopulations will be further purified using negative selection of monocytes with PanMonocyte beads by MACS. Progenitor cell composition will be identified using flow cytometry. HSPC proliferation assays (standard CFU assays) to assess myeloid colony-forming potential will be performed. In addition, single- cell RNA-sequencing and epigenetic assessment (ATAC-seq, ChIP-seq, DNA methylation) will be performed.

During debulking surgery, all visible tumor tissue will be removed by experienced surgeons.

During debulking surgery, an omental biopsy will be done.