Association of E2F3 expression with clinicopathological features of Wilms' tumors.

The transcription factor E2F3 plays an important role in controlling cell cycle progression and proliferation, and is overexpressed in various human cancers. The present study was undertaken to examine the expression of E2F3 and investigate its relevance in clinical and pathological features of pediatric Wilms' tumors. Twenty-six Wilms' tumor samples collected at the First Affiliated Hospital of Harbin Medical University underwent immunohistochemical staining for E2F3 protein expression by measuring the percentage of E2F3-positive cells and integrated optical density (IOD), and quantitative real-time polymerase chain reaction (qRT-PCR) for E2F3 mRNA expression. The expression of E2F3 protein and mRNA was detectable in all the Wilms' tumor samples with big variations (The average percentage of positive cells was 30.2%±23.5%, range 0.3%-75.6%; average IOD was 6.61×10(4)±3.92×10(4), range 2.32×10(4)-13.84×10(4); average relative mRNA unit was 0.54±0.38, range 0.03-1.31), but not in fetal kidney tissues. Wilms' tumors with aggressive features, such as higher stage, unfavorable histology and higher risk level, expressed higher levels of E2F3 protein and mRNA. The preliminary data indicate that E2F3 is frequently expressed in pediatric Wilms' tumors examined in the present study. E2F3 expression may be associated with Wilms' tumors, particularly those that have more aggressive features. However, further studies are needed to validate these pilot observations and to clarify the functional and mechanistic significance of this association.