ZEB1 and neoplasm: Furthermore, with analysis by a real-time qPCR, key transcriptional factors of the EMT such as Snail1, Snail2, Twist1, Twist2, Zeb1, and Zeb2, were found to be markedly expressed in Tg-6m tumor cells when normalized to Tg-3m tumor cells (Fig 4c and S3 Table).