The Twist1 transcription factor is known to promote tumor metastasis and induce 
Epithelial-Mesenchymal Transition (EMT). Here, we report that Twist1 is capable 
of promoting the formation of invadopodia, specialized membrane protrusions for 
extracellular matrix degradation. Twist1 induces PDGFRα expression, which in 
turn activates Src, to promote invadopodia formation. We show that Twist1 and 
PDGFRα are central mediators of invadopodia formation in response to various 
EMT-inducing signals. Induction of PDGFRα and invadopodia is essential for 
Twist1 to promote tumor metastasis. Consistent with PDGFRα being a direct 
transcriptional target of Twist1, coexpression of Twist1 and PDGFRα predicts 
poor survival in breast tumor patients. Therefore, invadopodia-mediated matrix 
degradation is a key function of Twist1 in promoting tumor metastasis.