Expression Of P-21 Activated Kinase 2 And Its Clinical Significance In Gastric Cancer

Objective: In order to evaluate the possibility of PAK2 being a new tumor marker or prognostic factor in gastric cancer, we investigated the expression of PAK2 in gastric cancer and analysed the correlation among clinicopathological features, prognosis and PAK2 through experiments.Methods: Gastric cancer tissues and paracancerous normal tissues(More than 5cm from cancer tissue, the pathological examination without cancer invasion)of 65 gastric cancer patients undergoing surgery at Shandong Tumor Hospital from January to December 2013 were included in this study. The mRNA expression of PAK2 gene was detected by Real-time quantitative reverse transcription-polymerase chain reaction(Real-time RT-PCR) and protein expression was detected by immunohistochemistry in tissues. Apply statistical methods to analyze its relationship with clinicopathological features and prgression free survival. Statistical methods includes independent samples T-test, chi square test and Kaplan-Meier, and P<0.05 indicates significant difference.Results: Real-time RT-PCR outcome revealed that the mRNA expression level of PAK2 in cancer tissues was 0.552±0.101 which was significantly higher than normal tissues 0.263±0.078, and the difference was statistically significant(P<0.05). Immunohistochemistry results showed that PAK2 staining in gastric cancer was stronger than normal tissue. PAK2 protein expression and mRNA were positively correlated. There was no significant correlations among the expression of PAK2 and sex, age, tumor size(P>0.05), but it’s closely related to the pathologic differentiation degree, depth of tumor invasion, lymph node metastasis and TNM stage(P<0.05). Compared to low expression group, PAK2 overexpression group has a higher recurrence/metastasis rate(44.44%). Follow-up study of gastric cancer patients reavealed that the median progression-free survival of high PAK2 expression group was 25.00±0.45 months which was significantly shorter than PAK2 low expression group(28.00±1.58months)and the difference was statistically significant(P<0.05).Conclusions: PAK2 is overexpressed in gastric cancer tissues; PAK2 expression was associated with poor prognostic factors such as pathologic differentiation degree, depth of tumor invasion, lymph node metastasis and TNM stage. Upregulation of PAK2 gene in the gastric cancer suggests that PAK2 may be involved in the carcinogenisis and development of gastric cancer; PAK2 is expected to become a poor prognostic factor for gastric cancer in the future.