Expression level of HAS1,2, and 3 in pan-cancer and pathological stages. (a) The TIMER2.0 database was used to display the differential expression of three types of HAS between specific tumors or their subtypes and adjacent normal tissues. When there are data for normal controls in tumors, they are shown together in a gray area. The red box reflects the gene expression in tumors, and the blue box reflects the gene expression in normal tissues; (b) significant downregulation of HAS1 in tumor tissues of LGG, OV, SKCM; (c) significant upregulation of HAS2 in tumor tissues of LGG, SKCM, and UCS; (d) significant downregulation of HAS3 in tumor tissues of SKCM; tumor types associated with the expression levels of HAS1 (e), HAS2 (f), and HAS3 (g) in different pathological stages (Stage I, II, III, and IV). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.