YY1 and lung cancer: Yin Yang 1 (YY1) is a ubiquitous transcription factor overexpressed in many types of cancers and is associated with poor prognoses.35, 36, 37 YY1 regulates EGFR and p53 gene expression.38, 39 To study the oncogenic effect of MCT-1 in a wild-type p53 background, normal breast epithelial MCF-10A cells and invasive lung cancer A549 cells were transfected with a V5-tagged MCT-1 expression construct or the vehicle (control).