P4 modulates AKT signaling in human neuroblastoma. (A) Representative photomicrographs (40x) of immunohistochemistry for phospho-Akt (Ser473) in tumor sections. The arrow shows the brown-stained phospho-Akt (Ser473) active cells. (B) Quantification of phospho-Akt (Ser473)-positive cells in different groups. Significant difference: *P < 0.05 compared with vehicle group. P50, P4 (50 mg/kg); P100, P4 (100 mg/kg).