CTAG2 (cancer/testis antigen 2) is a cancer-testis antigen with restricted expression in normal testicular germ cells and aberrant expression in various malignancies, making it an attractive target for cancer immunotherapy 12. The protein localizes to the centrosome where it interacts with Pericentrin and is necessary for directional cell migration in breast cancer cells 3. CTAG2 shows coordinate expression with other cancer-testis antigens like SPANX-A/C/D in breast cancer, where they promote distinct features of invasive behavior 3. The gene is expressed across multiple cancer types including myxoid and round-cell liposarcoma, where it shows consistent mRNA expression alongside PRAME 1, colorectal cancer with 17% of samples showing significant expression levels 4, and urothelial cancer where autoantibodies against CTAG2 are significantly elevated compared to healthy controls 5. CTAG2 expression can be upregulated in response to tumor suppressor activity, as demonstrated in osteosarcoma cells following LSAMP reexpression 6. However, autoantibodies against CTAG2 show limited early detection potential for ovarian cancer, with diagnostic sensitivity declining rapidly at lead times beyond 6 months 7. The shared epitopes between CTAG1 and CTAG2 enable dual-antigen targeting strategies for enhanced TCR-T cell cancer therapy 2.