FAS and rheumatoid arthritis: The clustering heat map showed the expression pattern of Necroptosis differential genes (NRDEGs) in RA samples and healthy control samples (Fig. 1A), and the correlation between NRDEGs is shown in Fig. 1B. FAS was positively correlated with MAPK8, BIRC, JAK2 and STAT1, and MAPK8 was negatively correlated with PYCARD, CASP1 and TNFSF10.