Relative expression of PRLR, JAK2, STAT5a and DGAT1 by Real-time PCR. The Ct value of SS was normalized to that of GAPDH, and the expression level of targets genes in cells transfected with pEGS/2SS-tPA or pEGS/2SS was calculated relative to cells transfected with pEGFP-N1. *P<0.05.