Figure 4. Characteristics and MPs of fibroblasts in OCCC. (A) UMAP plot of 7736 fibroblasts identified in OCCC fresh tumors by scRNA-seq (left, n=5). Radar plot showing proportions of fibroblasts subpopulation in newly diagnosed (n=2) and recurrent OCCC (n=3) (right). (B) UMAP plot of fibroblasts in OCCC FFPE samples by scFFPE-seq (left, n=8). Radar plot showing proportions of fibroblasts subpopulation in newly-diagnosed (n=4) and recurrent OCCC (n=4) (right top). Barplot showing proportions of fibroblasts subpopulation in ARID1A mutant (n=2) and wildtype (n=2) OCCC. (C) Heatmap showing five MPs of OCCC fibroblasts (n=13) extracted by NMF method. (D) Top: violin plot of MPs activity between fibroblasts from ND and RC tumors (Wilcoxon test, ***p<0.001). Middle and bottom: violin plots of MP3 activity and THBS1 expression level across fibroblasts subsets (Kruskal-Wallis test, ***p<0.001). (E) Representative IHC staining of POSTN in OCCC tumor, left: whole slide, right: high power field, 400×. (F) Survival curves of POSTN expression level in IHC cohort. Outcome: PFS, log-rank test. DL: double low expression of neither tumor marker nor stroma marker (POSTN ^low CD36 ^low CD47 ^low); SH: single high expression of either tumor marker or stroma marker (POSTN ^high CD36 ^low CD47 ^low or POSTN ^low CD36 ^high CD47 ^low or POSTN ^low CD36 ^low CD47 ^high); DH: double high expression of both tumor marker and stroma marker (POSTN ^high CD36 ^high CD47 ^high or POSTN ^high CD36 ^high CD47 ^low or POSTN ^high CD36 ^low CD47 ^high). (G) Scheme of cancer-associated fibroblasts isolation and coculture with tumor cells (left). Growth curve showed that supernatant of fibroblasts culturing medium promoted ovarian tumor proliferation (right, t-test, *p<0.05). FFPE, formalin fixed paraffin-embedded; IHC, immunohistochemistry; MPs, metaprograms; ND, newly diagnosed; OCCC, ovarian clear cell carcinoma; PFS, progression-free survival; RC, recurrent; UMAP, Uniform Manifold Approximation and Projection.