PRF1 and neoplasm: Granzyme B and perforin, which are expressed in cytotoxic T cells (Brandes et al., 2009; Voskoboinik et al., 2015), were expressed in both the iγδTs and PBγδT cells (Figure 4D), suggesting that the iγδTs, like authentic γδT, directly attach to and attack tumor cells with lytic granules carried by secretory lysosomes.