CDC42 and breast cancer: Melanoma differentiation-associated gene-9 (MDA-9), also known as syntenin-1 (SDCBP; syndecan binding protein), a member of the PDZ-domain-containing family [92], modulates the small Rho GTPases RhoA and Cdc42 to enhance invasion and cytoskeletal rearrangement in MDA-MB-231 and SUM159 breast cancer cells via TGFβ1 [93].