POU5F1 and embryonal carcinoma: It was reported that STAT3 activation of miR-21 and miR-181b-1 via PTEN and CYLD imposed feedback regulation on IL-6, which was in the upstream of STAT3 [44], and others published that Oct4 promoted the self-renewal and survival of embryonal carcinoma cells by feedback regulating AKT, which was in the upstream of Oct4 [45].