Up-regulation of RhoGDI2 in Human Breast Cancer and Its Prognostic Implications

Purpose Recent research has identified many genes and proteins that play specific roles in the process of systemic metastasis in various types of cancer. Rho GDP dissociation inhibitor 2 (RhoGDI2) has been shown to inhibit metastasis in human bladder cancer, but its role in breast cancer is controversial. Materials and Methods We examined the regulation and clinical significance of RhoGDI2 in Korean breast cancer patients by using proteomic approaches. Results By using a proteomic approach, we observed an increased expression of RhoGDI2 in human breast cancer tissues when compared to that of the normal breast tissues, and we validated its up-regulation in an independent cohort of 8 breast cancer patients. The clinical implication of a RhoGDI2 expression was investigated in 57 breast cancer patients by performing immunohistochemistry. RhoGDI2 did not show a significant association with the tumor size, lymph node metastasis, the histologic grade or the hormone receptor status. However, the patients with RhoGDI2-expressing tumors had significantly shorter disease-free survival (p=0.043; hazard ratio, 3.87) and distant metastasis-free survival (p=0.039; hazard ratio, 5.15). Conclusion Our results demonstrated a potential role of RhoGDI2 as a poor prognostic marker as well as a potential therapeutic target. The pro-metastatic nature of RhoGDI2 shown in our study may indicate its organ-specific role in cancer metastasis.