To assess antigen specificity, CT103a, nanoCAR, and Mock T cells were co-cultured with various GFP+-BCMA+ MM cell lines (MM1.S, RPMI-8226, and LP-1) as well as with a GFP+-BCMA- leukemia cell line (K562) at a 1:1 ratio for 24 to 48 h. This evidence concerns the gene TNFRSF17 and leukemia.