Inhibition of STAT3 suppressed the growth of tumors in vivo . A, BxPC3/Vector and shSTAT3 expressing (BxPC3/shSTAT3) cells were orthotopically implanted in a mouse model. Both group of animals were treated with gemcitabine (20 mg/kg body weight) or saline IP every three days until sacrifice. Primary tumors were surgically removed at week 4 and week 10 respectively for BxPC3/Vector and BxPC3/shSTAT3 group of animals. The isolated tumors were weighed to measure the growth of tumors and a representative data is shown for 10 animals in each group. Formalin fixed tumor tissue sections were analyzed for nuclear Ki-67 (B) and STAT3 (C) by immunohistochemistry. D, Total cellular proteins isolated from the tumors of BxPC3/Vector and BxPC3/shSTAT3 group of animals were analyzed by Western blot for the expression of STAT3Tyr705. β-actin and STAT3 are shown as a loading control.