RETN and teratoma: Although the amount of their production from the teratoma is unclear, these factors have been reported to circulate in wt serum on the order of ng/mL (Prl2c, resistin, insulin growth factor 2, angiopoietin, C1qtnf3, Postn, IGFBPs, PPBP), and pg/mL (colony-stimulating factor 1; Supplementary Data 6).