CTSS and atherosclerosis: We further attempted to identify the DEGs and the PPI network underlying the progression of atherosclerosis, which listed the nine upregulated cluster genes including ITGB2, C1QC, LY86, CTSS, C1QA, CSF1R, LAPTM5, VSIG4, and CD163, most of which encode cellular membrane proteins that are instrumental to signal transduction across membranes and chemical processing of incoming molecules (51, 52).