To further validate the clinical significance of CDK4 expression in patients with synovial sarcoma, we tested the expression levels of CDK4 in a human synovial sarcoma tissue microarray (TMA) by immunohistochemistry (IHC), and evaluated the correlation between CDK4 expression and the pathological characteristics of the synovial sarcoma patients. The gene discussed is CDK4; the disease is synovial sarcoma.