Therapeutic indication: Rheumatoid arthritisTarget: Tyrosine kinaseCategory 1• Genotoxicity findings indicate a potency to induce polyploidy• Immunosuppression in the repeated-dose toxicity study in rats• Malignancies observed with compounds of the same class (tofacitinib)• In monkeys tofacitinib induced lymphoma, related to immunosuppressive effect• Tumors reported in patients treated with JAK1/2 inhibitors, tofacitinib and ruxolitinib. This evidence concerns the gene JAK1 and lymphoma.