TAT and neoplasm: Tat-SID treatment of MDA-MB-231 3D cultures in basement membrane matrix that closely mimics the tumor microenvironment exerted a strong anti-invasive effect (Figure 4A) characterized by the presence of small (50-100 μM diameter), non-invasive spherically organized colonies in contrast to the large (>200 μM average diameter) disorganized colonies with invasive projections observed with Tat-Scr control (Figure 4A).