The ECT2 (epithelial cell transforming sequence 2) oncogene acted as a guanine nucleotide exchange factor for RhoGTPases, and regulates cytokinesis; thus, it may play a role in the pathogenesis of gastric cancer. In this study, we investigated the expression ECT2 gene in tissues and serum of gastric cancer patients to explore its clinical significance. ECT2 mRNA expression levels in tissues and serum were examined by RT-PCR, and ECT2 protein expression in tissue was evaluated by Western blot, and was further validated by immunohistochemistry and enzyme-linked immunosorbent assay at serum level. ECT2 level was significantly increased in the GC tissues and serum compared to normal control. ECT2 expression was positively correlated with the histologic differentiation, stages of TNM, and lymph node metastasis in GC (P < 0.05). Our results suggest that ECT2 plays an important role during GC progression and it may become a new diagnostic marker and therapeutic molecular target for management of GC.

ABSTRACT. Migration and invasion enhancer 1 (MIEN1) is a membrane-anchored protein that is highly expressed in various types of cancer, and is correlated with the PI3K/AKT pathway. The aim of this study was to investigate the expression of MIEN1 and its clinical pathological significance in breast cancer. We used immunohistochemical staining to examine the expression of MIEN1 in 40 samples of human breast cancer tissue and 10 samples taken from regions adjacent to normal breast tissue. The rate of detection of MIEN1 protein was 67.5%, which was significantly higher than that in adjacent non-cancerous breast tissue (0%, P < 0.05). The expression of MIEN1 correlated with age, World Health Organization grade, and lymph node metastasis, but not with tumor size or family history of cancer. KaplanMeier survival analysis showed that patients with positive MIEN1 protein expression had a lower overall survival rate than patients who did not express MIEN1. Downregulation of MIEN1 suppressed the expression of matrix metallopeptidase 9 by downregulating the expression of protein kinase B (also known as AKT) in breast cancer cells. Our results indicate that MIEN1 overexpression may facilitate migration and invasion in breast cancer, and MIEN1 is a potential molecular target for cancer chemotherapy.