SSX2 and hepatocellular carcinoma: CTAs comprise a range of self-derived proteins, such as melanoma-associated antigen A1 (MAGE-A1), MAGE-A3, New York esophageal squamous cell carcinoma antigen 1 (NY-ESO-1), and synovial sarcoma X break point gene 2 (SSX2), that can become immunogenic in HCC either by mutation or aberrant expression.