SNAI1 and cancer: The transcription factors Twist, Snail and Slug are known to promote EMT and cause the down regulation of E-Cadherin [10-12] As an in vitro model of MICs, under special culture conditions a heterogeneous population of cells can give rise to three-dimensional cancer spheres (cell clusters) which present enhanced expression of CD44 and display the capability of anchorage-independent growth [13].