PBX1 and hydrops fetalis: Indeed, the qPCR analysis showed that endogenous PBX1 levels increased with time during HF-iPSC reprogramming induced by SOMK transduction (Fig. 4b); PBX1 expression in these cells was significantly higher than that in HF-MSCs (P < 0.001) but lower than that in hESCs (Fig. 4a).