ESR1 and rheumatoid arthritis: In the first study case, on the one hand, we found that the differentially expressed genes (such as CREB1 [42,43], TNFSF10 [44], CD4 [45], and TNFSF12 [46]), and the non-differentially expressed genes (such as ESR1 [47], VDR [48], PPARG [49], ESR2 [50]) are RA-related genes.