Study On Expression Of PTEN And Its ReLationship With P-ERK, MMP-9 In Gastric Cancer

Objectives: To identify the role of PTEN, Tumor Suppressor Gene inhuman gastric cancer, we detected the expression level of PTEN and evaluated its relationship with clinicopathological parameters and expression of P-ERK, MMP-9 protein.Methods: Expression level of PTEN , P-ERK and MMP-9 protein was examined in 57 gastric cancer and correspondent adjacent normal tissues by irnmunohistochemistry S -P method.Results: 1. The positive rate of PTEN was significantly lower in gastric cancer (61.4%) than in normal tissues (100%, P<0.01). No correlation were found between expression level of PTEN and patients sex and age (P>0.05). Expression level ofPTEN protein decreased in lll,lVstage of gastric cancer compared to 1 ,llstage ofgastric cancer (P <0.01). The positive rate of PTEN oncoprotein was lower in poor differentiation tissues than in well differentiation tissues (P<0.01) and was lower in gastric cancer with lymphnode metastasis than in thoes without lymphnode metastasis (P<0.05). The deeper extent of invasiveness, the lower PTEN positive rate was. 2. The positive rate of P-ERK was significantly higher in gastric cancer (84.2%) than in normal tissues (12.3%, .P<0.01),and with the development of tissue invasiveness, lymphnode metastasis and TNM stage, expression level of P-ERK become more higher. 3. The positive rate of MMP-9 was significantly higher in gastric cancer (73.7%) than in normal tissues (19.3%, P <0.01), and expression level of P-ERK was related to extent of invasiveness, lymphnode metastasis and TNM stage (P<0.01). 4. A significant negative relationship was observed between the expression of PTENand P-ERK, MMP-9 protein in gastric cancer (r,= - 0.447, -0.462, P<0.01) .Conclusions: The data suggest that the expression level of PTEN protein was closely related to biological behavior of gastric cancer. Decrease or deletion of PTEN protein expression may not be able to effectively inhibit the over-activation of MMP-9 and Ras/RafTMEK/ERK signaling pathway, this will result in carcinogenesis, invasiveness and metastasis.