IRF5 and synovial sarcoma: The largest available genome-wide association study on SS recognized variants in genomic regions encoding for constituents of the type I cytokine pathway, such as IL12A (encoding the p35 subunits of IL12), IRF5 (encoding a transcription factor that activates among others the gene for the p40 subunit of IL-12), and STAT4 (encoding the homonymous transcription factor that activates IFNγ expression) as risk factors in SS (12).