Overexpression of Rab25 (at levels close to those observed in aggressive ovarian cancers; Caswell et al., 2007; Cheng et al., 2004) also significantly reduced the width of protrusions extended from cells moving in the 3D CDM, and most of these protrusions were tipped by filopodia alone (Fig. 2A–C). The gene discussed is RAB25; the disease is ovarian cancer.