The AR target gene PIP rescues tumor growth in Postn-null mice. Q-PCR expression analysis shows that the AR target genes prolactin-induced protein (PIP; *
P <0.05) (A) and androgen-binding proteins ε and ζ (B) are markedly induced in Postn-null tumors (*
P <0.005). (C) Tumor volume measurements at 28 days post-injection of PIP- or Postn-expressing Met-1 cells. Expression of PIP in Met1-cells rescues their subcutaneous growth defect in FVB/N Postn-null females (*
P <0.01). Postn-expressing cells could not rescue the growth deficit in Postn(-/-) mice. Inset: Ethidium bromide-stained PCR reaction showing expression of exogenous PIP in Met-1 cells.