Affiliations: [a] Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in Southern China, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong, China | [b] Department of Biotherapy, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong, China | [c] Department of Abdominal Oncosurgery, The Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China | [d] Department of Gastric and Pancreatic Surgery, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong, China | [e] Department of Emergency Medicine, Sun Yat-Sen Memorial Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China | [f] Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
Correspondence:
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Corresponding author: Peng Wang, Department of Emergency Medicine, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou 510120, China, Tel.: +86 20 81332084; Fax: +86 20 81332410; E-mail: pengwangsysu@foxmail.com.
Note: [1] These authors contributed equally to this work.
Abstract: BACKGROUND: Rap1GAP, a member of the family of GTPase-activating proteins, is reported to be involved in cancer development and progression. OBJECTIVE: The study aimed to investigate the expression and prognostic value of Rap1GAP in gastric cancer patients. METHODS: Real-time quantitative polymerase chain reaction and western blotting were performed to examine Rap1GAP expression in tumorous and matched adjacent non-tumorous gastric tissues. Immunohistochemical staining was used to analyze Rap1GAP expression in 456 gastric cancer tissues. The correlation between Rap1GAP expression level and clinicopathological features as well as gastric cancer prognosis was analyzed. RESULTS: Rap1GAP expression was remarkably decreased in tumor tissues at mRNA (p= 0.012) and protein (p= 0.034) level. Clinicopathological analysis revealed that low Rap1GAP expression was significantly correlated with tumor size (p= 0.033), histological grade (p= 0.034), T classification (p= 0.012), N classification (p= 0.006) and clinical stage (p= 0.005). Kaplan-Meier survival analysis revealed the association between low Rap1GAP expression and poor survival in gastric cancer patients. Furthermore, multivariate Cox regression analysis showed that Rap1GAP expression was an independent prognostic factor (p= 0.02). CONCLUSION: Rap1GAP may play a significant role in gastric cancer progression and act as a valuable prognostic marker for gastric cancer.
