Expression of insulin-like growth factor II mRNA-binding protein 3 predicts early recurrence and poor prognosis in intrahepatic cholangiocarcinoma.

INTRODUCTION: Insulin-like growth factor-II mRNA-binding protein 3 (IMP3), a newly identified oncofetal RNA-binding protein, plays a pivotal role in the regulation of cell growth and migration during early stages of embryogenesis, and is found to be expressed in various human cancers. In this study, we elucidated the clinicopathological significance of IMP3 expression in intrahepatic cholangiocarcinoma (ICC).
METHODS: From March 1995 to December 2003, 61 surgically resected, unifocal primary ICCs were studied. IMP3 protein expression was detected by immunohistochemical staining.
RESULTS: IMP3 protein was expressed in 25 of 61 ICCs (41.0%). In addition to correlating with tumor grade (p = 0.0276), tumor stage (p = 0.0059), lymphovascular invasion (p = 0.0198), serum carbohydrate antigen 19-9 level (p = 0.0146), IMP3 expression predicted early tumor recurrence (ETR) (p = 0.0059) and was a strong indicator of worse disease-free survival (p = 0.0001) and overall survival (p = 0.0007). Even though we did not find that IMP3 expression exerted prognostic impact independent of tumor stage, multivariate analysis confirmed that IMP3 expression was an independent risk factor of high-stage tumor and ETR (p = 0.0170, and p = 0.0052, respectively), and thus it contributed to poor prognosis in ICC patients.
CONCLUSIONS: IMP3 expression can serve as a novel maker for ETR and prognostic prediction, and may be a target for adjuvant therapy of patients with ICC after tumor resection.