SPARC and cancer: Strikingly, SPARC emerged as the top gene (r ≥ 0.9) correlating with CAFs across various cancer types (Additional file 1: Table S10, Fig. 4), while its expression was commonly upregulated across different tumors, including cancer of bladder, breast, bile ducts, colon, esophagus, brain, head and neck, liver, and stomach (Additional file 2: Fig. S3).