Given that CD8+ T cells are effective killers of malignant cells and are often used in CAR-based immunotherapies to enhance tumor eradication [52], a key hurdle for the successful in vitro development of cytotoxic T cells is the progression of CD3+/−CD4+CD8+ immature T cells through to TCR+CD3hiCD8+CD4− cells. This evidence concerns the gene CD4 and neoplasm.