All of our data suggest that MSCs can protect against the cytotoxic effects of CYP in producing infertility in male chemotherapy patients that may be by two different mechanisms which may be by preserving pre-existing spermatogonial stem cells (SSCs) or trans-differentiating into SSC-like cells to generate spermatocytes (Kubota and Brinster, 2018; Ibtisham and Honaramooz, 2020; Diao et al., 2022). This evidence concerns the gene PPIG and Infertility.