Clinical significance of RacGAP1 expression at the invasive front of gastric cancer

Background Rac GTPase activating protein 1 (RacGAP1) plays a regulatory role in cell growth, transformation and metastasis. The aim of this study was to clarify the association between RacGAP1 expression and clinical outcome in patients with gastric cancer. Methods A total of 232 gastric cancer patients in our institute who underwent surgery without preoperative treatments were enrolled in this study. We investigated RacGAP1 expression using immunohistochemistry (IHC) and evaluated IHC scores calculated by the percentage of positive cells and intensity and its expression at the invasive front. RACGAP1 expression was also assessed. Results RacGAP1 expression was observed in the nuclei of gastric cancer cells. Evaluation by IHC score showed no significant correlations with clinicopathological variables except for histological differentiation. In transcriptional analyses, RACGAP1 expression was elevated in diffuse type gastric cancer than intestinal type without a significant difference. We observed significant correlations of RacGAP1 protein expression at the invasive front with older age, tumor size, lymph node metastasis, lymphatic invasion, vascular invasion and advanced stage. Patients with RacGAP1 protein expression at the invasive front had significantly poorer prognosis than those without it ( P