ZEB1 and cancer: Previous studies show that mRNA levels of various EMT transcription factors, including ZEB1, were not significantly different among normal tissues and tumor tissues.15 Yet, malignant tumors frequently displayed high protein expression of the EMT transcription factors in the absence of overt mRNA changes.15 These findings support the idea that posttranscriptional mechanisms, such as the ones regulating protein stability and degradation, could maintain high levels of the EMT transcription factors in tumor cells.