Growth inhibition of SPC-A1 xenografts. Followed by systemic treatment with LPEI-complexed EGFR-specific siRNA, the growth of SPC-A1 xenografts has been inhibited because of decreased EGFR expression. Subcutaneous xenografts generated as described above. (A) Intraperitoneal injection performed every 3 days with 0.6 nmol LPEI/siRNA-EGFR (open circles), LPEI/siRNA-NEG (closed circles), and 5% GS (triangles), respectively. Tumor volumes recorded every 3 days. Data expressed as mean of six mice in each group. (B) Tumor weight comparisons between three groups at endpoint of experiment. (C) IHC and (D) Western blot analysis for EGFR protein levels. All the results are shown as the mean±standard error of numbers obtained from 6 animals in each group. *P < 0.05; **P < 0.01.