The present invention relates to compositions and methods for the modulation of metastatic and mesenchymal cell growth and mobility via the regulation of the formation of Twist/Twist homodimers and Twist/E heterodimers. The present invention also relates to methods for screening agents and compound libraries for molecules that function to modulate the formation of Twist/Twist homodimers, Twist/E protein heterodimers or their upstream or downstream effector molecules
