MAP2K4 and rheumatoid arthritis: Associations between 20 genes from this sub-network (XCL1, VCAM1, TRPV1, TRPC1, SPP1, RUNX1, RAC1, PRKCZ, NR3C1, NFKB1, MAP2K4, JUN, ITGB1, ITGAV, HMGB1, HLA-DMB, HLA-C, ERBB2, EPAS1, CCL21) and RA were verified by literature retrieved from the NCBI PubMed module and OMIM, as shown in Figure 2b.