POU5F1 and pituitary tumor: In this study, we hypothesize the potential presence of PGC-like cells in the pituitary gland, and these cells may differentiate into iGCTs during the complex and frequent regulation of the hypothalamic-pituitary-gonadal axis (HPGA).We analyzed the expression of four germ cell markers-MVH, OCT4, C-kit, and PLZF-using immunohistochemistry, Western blotting, and real-time quantitative PCR in human pituitary tissues, pituitary tumors, and pituitary germ cell tumors.