Involvement of highly significant DEGs including SLCO1A2 [52], OLFM4 [53], RTKN2 [54], CYP1A1 [55], and MUC5AC [56] plays a key role in rheumatoid arthritis development.Highly significant DEGs including OLFM4 [57], RTKN2 [58], CYP1A1 [59], MUC5AC [60], CYP2A6 [61], PCK1 [62], and PITX1 [63] have been reported to encourage the development of lung cancer. This evidence concerns the gene RTKN2 and rheumatoid arthritis.