STAT3 and rheumatoid arthritis: RA patients are known to have a high incidence of lung cancer.[3] It has also been reported that RA activity and severity are associated with lung cancer,[16] suggesting that RA inflammation may influence the mechanism of cancer development.[17] Notably, IL-6/JAK1-induced phosphorylation of STAT3 initiates the transcription of various genes that promote proliferation and prevent apoptosis[18]; subsequently, the signaling cascade increases WNT5A, which is upregulated in various cancers, including lung cancer, and is associated with the development of metastasis.[19]