SSX3 (SSX Family Member 3)
Cancer/testis antigen gene involved in synovial sarcoma and immune evasion
Gene Information Card
| Symbol | SSX3 |
|---|---|
| Full Name | SSX family member 3 |
| Gene Type | protein-coding |
| Chromosomal Location | Xp11.23 |
| NCBI Gene ID | 6759 ncbi.nlm.nih.gov/gene/6759 |
| Ensembl ID | ENSG00000179295 |
| UniProt ID | Q99909 |
| OMIM ID | 300328 |
| HGNC ID | 11337 |
| Aliases | CT5.3, SSX3, SSX3A |
Description
SSX3 (SSX family member 3) is a protein-coding gene belonging to the SSX family of cancer/testis antigens. The gene is located on chromosome Xp11.23 and is normally expressed in testis but aberrantly expressed in various cancers, including synovial sarcoma. The encoded protein is involved in transcriptional regulation and may play a role in cell cycle control and immune evasion. SSX3 is a target for cancer immunotherapy due to its restricted normal expression and frequent upregulation in tumors.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Synovial sarcoma | SSX3 fusion with SS18 (SYT) drives oncogenesis via chromatin remodeling | PMID: 7530509; COSMIC |
| Melanoma | SSX3 re-expression contributes to immune evasion and tumor progression | PMID: 10417712 |
| Lung cancer | SSX3 upregulation associated with poor prognosis and metastasis | PMID: 21532982 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.5 | High |
| Skin | 0.3 | Low |
| Lung | 0.1 | Low |
| Brain | 0.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A-673 (Ewing sarcoma) | 0.0 | No expression |
| SK-MEL-28 (melanoma) | 8.2 | Moderate expression |
| NCI-H1299 (lung cancer) | 5.1 | Low expression |
| SW982 (synovial sarcoma) | 15.3 | High expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1Val) | Missense | <0.1% | Loss of start codon; likely loss of function |
| c.123C>T (p.Pro41=) | Synonymous | 0.2% | No effect on protein sequence |
Mutation functional classification
Loss of Function (LOF)
No confirmed loss-of-function mutations reported in COSMIC or ClinVar.
Gain of Function (GOF)
SSX3 fusion with SS18 (SYT) in synovial sarcoma is a gain-of-function oncogenic event.
Dominant Negative (DN)
Not documented for SSX3.
View complete mutation data：
Gene Ontology (GO)
| • nucleus (GO:0005634) | • transcription corepressor activity (GO:0003714) |
| • regulation of transcription by RNA polymerase II (GO:0006357) | • cell cycle (GO:0007049) |
| • cell proliferation (GO:0008283) |
Pathways
• Synovial sarcoma pathogenesis (SS18-SSX fusion)
• Cancer/testis antigen signaling
Protein Summary
The SSX3 protein is a 188-amino-acid nuclear protein containing a KRAB-like repression domain and a SSX repression domain. It functions as a transcriptional corepressor by interacting with polycomb group proteins and histone deacetylases. In normal tissues, expression is restricted to testis, but it is aberrantly activated in several cancers, particularly synovial sarcoma where it fuses with SS18. The protein contributes to tumorigenesis by altering chromatin structure and gene expression programs that promote cell proliferation and immune evasion.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SSX3 Knockout HEK293 Cell Line | EDJ-KQ50944 | Human | 10214 | Details Get a Quote |
| SSX3 Knockout HeLa Cell Line | EDJ-KQ55347 | Human | 10214 | Details Get a Quote |
| SSX3 Knockout A-549 Cell Line | EDJ-KQ63827 | Human | 10214 | Details Get a Quote |
| SSX3 Knockout HCT 116 Cell Line | EDJ-KQ72288 | Human | 10214 | Details Get a Quote |
