TRAV2 and synovial sarcoma: The high expression of clonotype genes (TRBV7-2 and TRAV2) in cluster 6, the highest frequency of TCRα clonotype TRAV2 and TCRβ clonotype TRBV7-2 in the SS patient’s skin lesion, the increased aberrant expression of tumor-associated genes KIR3DL2 (CD158k) and a decrease in CD7 in cluster 6 indicated that cells in cluster 6 were mainly malignant CD4+ T cells [9, 19] (Figs. 2C, S4A-B).