ZEB1 and neoplasm: Over the last several years, a number of groups have described the involvement of ZEB1 (ZFHX1A) and SIP1 (ZFHX1B) – both individually and cooperatively – in the transcriptional repression of the E-cadherin gene during the epithelial-to-mesenchymal transition of carcinoma cells subjected to the low oxygen/ischemic/reducing environment in the interior of a growing tumor mass (a necessary step in the progression of tumors towards metastasis, [refs. 51]–[54]).