Objective:To observe the effect of liver kinase B1/serine-threonine kinase 11(LKB1)on the progression of prostate cancer by studying the expression of LKB1

transforming growth factor-β1(TGF-β1)in prostate cancer tissues and cells. Methods:Two cell lines(normal prostatic epithelial cell line RWPE-1

prostatic carcinoma cell lines PC-3)were detected by SP method

RT-PCR and Western blot in order to detect the expression of LKB

TGF-β1 m RNA and protein on human prostatic hyperplasia and prostate cancer tissues. Results :The positive rates of LKB1 and TGF- β1 were 55% and 70% in prostatic carcinoma

and 83.3% and 40%in prostatic hyperplasia. The positive rates of LKB1 were lower in prostatic carcinoma than in prostatic hyperplasia(P<0.05)

and the positive rates of TGF-β1were higher in prostatic carcinoma than in prostatic hyperplasia(P <0.05). However

LKB1 expression had a negative correlation with TGF-β1(r=-0.373

P=0.018). The relative levels of LKB1 protein and m RNA were higher in prostatic hyperplasia than in prostatic carcinoma(P<0.01). However

the relative levels of TGF-β1 protein and m RNA were higher in prostatic carcinoma than in prostatic hyperplasia. The level of LKB1 protein and m RNA were higher in prostatic epithelial cell line RWPE-1than in prostatic carcinoma cell line PC-3(P<0.01)by immunocytochemistry

Western blot and RT-PCR analysis. However

the expression of TGF-β1was higher in prostatic carcinoma cell line PC-3 than in prostatic epithelial cell line RWPE-1(P<0.05). Conclusion:The down-regulated expression of LKB1

while the excessive expression of TGF-β1 may play synergetic roles in the prostatic carcinogenensis. LKB1 gene may be a potential target for researching the molecular of prostatic cancer tumorgenesis and evolution by exploring the interactive mechanism of LKB1 and TGF-β1.