Oncofetal protein, IMP-3, a potential marker for prediction of postoperative peritoneal dissemination in gastric adenocarcinoma

Background The aim of this study was to determine the expression of insulin-like growth factor-II messenger RNA (mRNA)-binding protein-3 (IMP-3) and its clinical significance in gastric cancers, as well the prognostic value of its expression in the peritoneal lavage fluid after surgery. Methods IMP-3 expression was examined by immunohistochemistry in 96 primary gastric tumors. IMP-3 mRNA expression in peritoneal lavage fluid obtained at laparotomy was determine by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Results Positive staining for IMP-3 was observed in 74% (71/96) of the tumors. IMP-3 expression in gastric tumors correlated significantly with worst overall survival (OS) and recurrence-free survival. Multivariate analyses identified pathological N stage and IMP-3 expression as significant independent prognostic factors for disease-free survival. Eight (28%) of 36 peritoneal lavage samples were cytologically negative but positive for IMP-3 mRNA expression by RT-PCR. The OS of patients with IMP-3-positive peritoneal lavage was significantly worse than of those with negative expression. Conclusions IMP-3 expression in primary gastric tumors was an independent poor prognostic factor. IMP-3 mRNA expression in peritoneal lavage fluid was a predictor of recurrence after surgery in gastric cancer and a marker of poor prognosis.