This suggests that in breast cancer cells responding to factors secreted by brain endothelial cells, EGF controls filopodia via a pathway that does not involve CDC42, and filopodia may be dispensible for elongation and invasiveness during metastatic extravasation37,38; moreover it has been demonstrated previously that filopodia formation may be independent of CDC4238. The gene discussed is EGF; the disease is breast carcinoma.