By comparing the gene expression profiles of ESC- and E-iPSC-induced teratomas, authors identified nine genes that were over-expressed in iPSC-induced teratomas and found teratoma antigen-specific functional T cells in these animals, suggesting that rejection of iPSC-induced teratomas was mediated by teratoma-associated antigen-directed T cell responses, as the CD4−/− and CD8−/− mice could form teratomas (5). This evidence concerns the gene CD8A and teratoma.