We identified 27 candidate genes for perturbation, including a TCF7L2 (transcription factor 7-like 2 (T-cell specific, HMG-box)) polymorphism assumed to be associated to rheumatic arthritis53 and CDKN1A (cyclin-dependent kinase inhibitor 1A (P21, Cip1)), whose decreased expression has been linked to an increased risk to develop autoimmune diseases, such as rheumatoid arthritis.54 The drugs having more gene targets in the disease network are benzo(a)pyrene (14 targets), copper sulfate (12 targets), TCDD (12 targets), valproic acid (12 targets) and cyclosporine (10 targets). Here, CDKN1A is linked to rheumatoid arthritis.