Expression of receptor tyrosine kinase Axl and its ligand in prostate cancer and its clinical significance.

Objective:To examine the expression of receptor tyrosine kinase(RTK)Axl and its ligand Gas6 (growth arrest-specific gene 6) protein in prostate cancer (PCa) tissues and their relation with pathological characteristics of PCa. Methods:Forty-five PCa tissues and 32 benign prostatic hyperplasia tissues (2007 to 2008,Changhai Hospital) were obtained during surgery or kidney puncture. Expression of Axl and Gas6 protein in PCa cell lines LNCaP,PC-3 and DU-145 was analyzed by Western blotting. Expression of Axl and Gas6 protein in PCa tissues or benign prostatic hyperplasia tissues was examined by immunohistochemisty. Results:Axl expression was higher in highly invasive DU-145 and PC-3 cells than that in lowly invasive LNCaP cells. Expression of Gas6 in DU-145,PC-3 and LNCaP cells was similar. Expression of Axl and Gas6 protein in PCa tissues was significantly higher than that in benign prostatic hyperplasia tissues as detected by immunohistochemisty(68.9% vs 21.9%; 53.3% vs 15.6%,all P0.01). Expression of Axl and Gas6 protein in PCa tissues was closely correlated with Gleason scores and metastasis of PCa (P0.05). Conclusion:Expression of Axl and Gas6 in PCa is closely correlated with the malignancy degree and metastasis of PCa.