Notably, we also found a cluster of cells that exhibited higher expression of a set of cell cycle-related genes (CENPF, NUSAP1, PTTG1, STMN1, TOP2A, and TUBA1B) (Fig. 2b; Table S4), which was consistent with proliferative CAFs (pCAFs) in a previous pan-cancer study of CAFs [10]. This evidence concerns the gene PTTG1 and cancer.