Objective:To build a moderate lung cancer orthotopic transplantation tumor model

and to investigate the expression of metabolic pathway in the this model. Methods:After optimizing the dose of anesthetic medicine and operation procedures of endotracheal orthotopic transplantation

5×106 of A549 cells were planted into male nude mice（6-8 weeks old

n=10）lungs. And the blank control（only PBS transplant）was carry out on the same condition mice（n=4）. Then the tumor formation rate

location

anatomy and the expression of signal transducer and activator of transcription 3（STAT3）

protein kinase B（AKT） and mammalian target of rapamycin（m TOR）were studied. Results:The best surgical anaesthesia condition was by intraperitoneal injection of 75 mg/kg body weight pentobarbital sodium. After the improvement of the operation procedure

the total tumor formation rate was 80.0%

and mainly located in the upper lobe of the right lung. The tumor showed a significant glandular cancer structure with poor differentiation degree

and more proliferating cell nuclear antigen（PCAN）-positive cells compared with normal lungs. The levels of phosphorylation of STAT3

AKT and m TOR and the ratio of p STAT3/STAT3

p-AKT/AKT

p-m TOR/m TOR in lung tumors were significantly higher than those in normal lung tissues

the difference was statistically significant differences（t=-4.381

-4.462

-4.951;P=0.041

0.011

0.038 respectively）.Conclusion:The improved endotracheal orthotopic transplanta-tion lung cancer model is a simple

low cost

stable model

and metabolic pathways play a role in the development and progression of lung cancer.