COL1A1 and neoplasm: Clusters 1 and 4 represented fibroblasts based on COL1A1 and DCN expression, whereas cluster 7 represented vascular endothelial cells based on the expressions of VWF, PLVAP, and PECAM1. Cluster 3, adjacent to the fibroblast cluster, was identified to include tumor cells based on the high expression of keratin-related genes (e.g., KRT18) (Figures 1B, 1D, and S1D).