Expression of Rac-1 related to tumor depth, lymph node metastasis and patient prognosis in esophageal squamous cell carcinoma

Rac-1, which is a member of the Rho guanosine triphosphatase (GTPase) family, has been demonstrated to play an important role in cancer invasion and metastasis. In this study, we investigated the clinical and prognostic significance of Rac-1 in esophageal squamous cell carcinoma (ESCC). The protein and messenger ribonucleic acid (mRNA) levels of Rac-1 in normal esophageal epithelia cells and paired ESCC tissues were examined by Western blot and reverse transcription polymerase chain reaction. The results showed that Rac-1 was upregulated at the protein and mRNA levels in ESCC cancerous specimens compared with normal esophageal tissues. We then examined the correlation between Rac-1 expression and clinicopathological features using immunochemical analysis of 233 surgically resected ESCC. Rac-1 protein was expressed in 228 (97.85 %) cancer tissues with cytoplasm staining, and there were significant correlations between Rac-1 expression and tumor location (P = 0.045), tumor stage (P = 0.020), tumor depth (P = 0.023) and lymph node metastasis (P = 0.009). The overall survival and disease-free rates of ESCC patients with high Rac-1 expression were much lower than those with low Rac-1 expression (P < 0.001; P < 0.001, respectively). Multivariate analysis showed that high Rac-1 expression and lymph node metastasis were two independent factors for poor survival (P < 0.001; P < 0.001, respectively). The results in this study indicate, for the first time, that Rac-1 is involved in the invasion and metastatic progression of ESCC and may be a potential marker for evaluating the prognosis of ESCC patients and a therapy target for ESCC.