A missing link between RON expression and oncological outcomes in resected left-sided pancreatic cancer.

Alteration and activation of recepteur d'origine nantais (RON) expression is known to be associated with cancer progression and decreased survival in various types of human cancer, including pancreatic cancer. Therefore, in the present study, RON expression levels were determined in resected left-sided pancreatic cancer to evaluate the potential oncological role of RON in the clinical setting of distal pancreatic cancer. From January 2005 to December 2011, a total of 57 patients underwent radical distal pancreatectomy for left-sided pancreatic cancer. Ductal adenocarcinoma was confirmed in all patients. Among these patients, 17 patients who received preoperative neoadjuvant treatment and 7 patients without available paraffin-embedded tissue blocks were excluded from the present study. RON expression in a the pancreatic cancer cell lines ASPC-1, BxPC-3, MiaPaCa-3 and Panc-1, as well as in resected left-sided pancreatic cancer specimens was determined by Western blot analysis. RON and vascular endothelial growth factor (VEGF) overexpression in resected left-sided pancreatic cancer was also evaluated by immunohistochemistry using pre-diluted anti-RON and anti-VEGF antibodies. An association was identified between the oncological outcome and RON overexpression. Increased levels of RON expression were observed in two pancreatic cancer cell lines, AsPC-1 and BxPC-3. RON overexpression was detected in specimens from 15/33 patients (45.5%) using immunohistochemistry. No significant association was identified between RON overexpression and VEGF overexpression (25.5 vs. 87.9%; P=0.667). No significant differences in disease-free survival or disease-specific survival associated with RON overexpression were identified. Although the results of previous studies have suggested that RON is a potential target for the treatment of pancreatic cancer, in the present study no association between RON overexpression and any adverse oncological effect was identified.