CRABP1 and synovial sarcoma: Additionally, many other genes that have been previously related to synovial sarcomas, such as the SSX4 gene, EGFR and SALL2 [29], components of the retinoic acid pathway (CRABP1 and RARG) as well as retinoic acid induced genes (IRX5 and TGFβ2) [24], were also included in this module.