该基因产物属于高度同源滑膜肉瘤X（SSX）断点蛋白家族。这些蛋白可能作为转录抑制因子发挥作用。它们还能够在癌症患者中引起自发的体液和细胞免疫反应，是基于癌症疫苗的免疫治疗的潜在有用靶点。ssx1、ssx2和ssx4基因参与了所有滑膜肉瘤的t（x；18）易位。这种易位导致18号染色体上的滑膜肉瘤易位基因与X号染色体上的一个SSX基因融合。Xp11号染色体包含一个片段性重复，导致两个相同的滑膜肉瘤副本，X断点4，SSX4和SSX4B，在尾对尾方向。这个基因，ssx4，代表更多的端粒拷贝。两个编码不同亚型的转录变体已被鉴定为该基因。
The product of this gene belongs to the family of highly homologous synovial sarcoma X (SSX) breakpoint proteins. These proteins may function as transcriptional repressors. They are also capable of eliciting spontaneously humoral and cellular immune responses in cancer patients, and are potentially useful targets in cancer vaccine-based immunotherapy. SSX1, SSX2 and SSX4 genes have been involved in the t(X;18) translocation characteristically found in all synovial sarcomas. This translocation results in the fusion of the synovial sarcoma translocation gene on chromosome 18 to one of the SSX genes on chromosome X. Chromosome Xp11 contains a segmental duplication resulting in two identical copies of synovial sarcoma, X breakpoint 4, SSX4 and SSX4B, in tail-to-tail orientation. This gene, SSX4, represents the more telomeric copy. Two transcript variants encoding distinct isoforms have been identified for this gene.