Insulin-like growth factor II messenger RNA-binding protein-3 is an independent prognostic factor in uterine leiomyosarcoma.

Aims: The aim of this study was to identify the prognostic factors of uterine leiomyosarcoma (ULMS).

Methods And Results: We reviewed 60 cases of surgically resected ULMSs and investigated conventional clinicopathological factors, together with the expression of insulin-like growth factor II messenger RNA-binding protein-3 (IMP3), hormone receptors and cell cycle regulatory markers by immunohistochemistry. Mediator complex subunit 12 (MED12) mutation analysis was also performed. Univariate analyses revealed that advanced stage (P < 0.0001), older age (P = 0.0244) and IMP3 expression (P = 0.0011) were significant predictors of a poor outcome. Multivariate analysis revealed advanced stage (P < 0.0001) and IMP3 (P = 0.0373) as independent predictors of a poor prognosis. Expressions of cell cycle markers and hormone receptors, and MED12 mutations (12% in ULMSs) were not identified as prognostic markers in this study.

Conclusions: IMP3 expression in ULMS could be a marker of a poor prognosis.