In the rheumatoid arthritis pathway, 18 genes were expressed differentially, including ANGPT1, ATP6V0A1, ATP6V1A, ATP6V1C2, ATP6V1G1, CCL2, CTSK, CXCL1, CXCL12, CXCL5, CXCL6, HLA-DQA1, ICAM1, IL6, JUN, MMP1, MMP3, and TGFB3. Here, CTSK is linked to rheumatoid arthritis.