To test whether a decitabine-induced reexpression strategy for PKD1 can be an efficient way to treat breast tumor growth and metastasis in vivo, we orthotopically implanted MDA-MB-231 cells either stably expressing scrambled shRNA control or two different specific shRNA sequences for PKD1 into the mammary fat pads of female NOD scid mice. Here, PKD1 is linked to breast neoplasm.