Interestingly, BACH1’s target genes with the lowest edge weight (Q1) had a significantly lower measured fold change compared to those with the highest weights (Q4) (0.3 versus 0.5, P = 3.46 × 10−7, t test), indicating a good agreement between the measured gene expression fold changes with the regulatory edge weights of the BACH1 FLS networks (Fig 5B), further validating the RA FLS network we constructed. This evidence concerns the gene BACH1 and rheumatoid arthritis.