Myosin X (MYO10) promotes tumour invasion by transporting integrins to filopodial tips in breast cancer cells. The role of MYO10, however, is not well defined. By examining the expression of MYO10 in breast cancer cells and clinical samples, with the aid of a fluorescein-based assay and a xenograft mouse model, the mechanism underlying the effects of MYO10 have started to become clear. Researchers have shown that elevated levels of MYO10 correlated with hormonal receptor expression status (oestrogen and progesterone) as well as poor cellular differentiation and lymph-node metastasis. When MYO10 was silenced, cell migration and invasion was reduced. In a mouse model, silencing of MYO10 decreased levels of invasive growth and lung metastases. The ability of MYO10 to promote invasion was shown to be associated with invadopodia. Thus, high levels of MYO10 increase breast cancer aggressiveness by forming invadopodia.