POU5F1 and infection: This composite may drive pluripotency via SOX2‐OCT4 and switch on lineage‐related genes through Oct4's recruitment of Tcf/Lef factors.23 As a high level of OCT4 expression was detected in the Eca109 cell line,28 we inhibited the expression of OCT4 via the lentiviral infection system with plasmid vectors encoding OCT4‐shRNA.