Transcriptional enhancer factor TEF-1 also known as TEA domain family member 1 (TEAD1) and transcription factor 13 (TCF-13) is a protein that in humans is encoded by the TEAD1 gene. TEAD1 was the first member of the TEAD family of transcription factors to be identified. TEAD1 is expressed in various tissues including skeletal muscle, pancreas, placenta, lung, and heart. Analysis of cancer transcriptome databases (www.ebi.ac.uk/gxa) showed that TEAD1 is dysregulated in several types of cancers. First in Kaposi sarcoma there is a 300-fold increase in TEAD1 levels. Moreover, the increase of TEAD expression can be detected in basal-like breast cancers, fallopian tube carcinoma, and germ cell tumors. Otherwise, in other types of cancer TEAD expression is decreased, for example in other breast cancer types and in renal or bladder cancers. This dual role can be explained by the different targets and the differential regulation of target genes by TEAD transcription factors. Finally recent studies showed that TEAD1 and YAP in ovarian cancer can induces cell stemness and chemoresistance. And that genetic variant of TEAD protein and YAP are enriched in some cancers.