STAT4 and synovial sarcoma: Genes IRF5 (interferon regulatory factor 5), CXCR5 (C-X-C chemokine receptor type 5), TNIP1 (TNFAIP3-interacting protein 1), IL12A (interleukin-12 subunit alpha), BLK (B lymphoid tyrosine kinase), and STAT4 (signal transducer and activator of transcription 4) have been proposed in several studies as gene candidates for SS susceptibility (Lessard et al., 2013;Burbelo et al., 2014).