POU5F1 and lung adenocarcinoma: CSCs, as another type of stem cells, have been shown to contribute to tumor recurrence, resistance to chemo- and radiotherapy and malignant development.5,6 Recently, a series of studies demonstrated that these transcription factors are highly expressed in glioma,7 pancreatic cancer,8,9 breast cancer,10 lung adenocarcinoma11 and hepatoma.12 In 2010, Chiou et al.11 found that the overexpression of OCT-4 and Nanog promoted the formation of spheres with an increase of CD133 in lung adenocarcinoma.