Clinical outcome and biological predictors of relapse following nephrectomy only for very low risk Wilms tumor (VLR WT): A report from Children’s Oncology Group AREN0532.

10023 Background: An earlier study of observation only following nephrectomy for VLR WT defined as stage I, age 85% and Overall Survival (OS) of > 95%, and 2) to validate prognostic biomarkers. Methods: From 10/30/2006-8/12/2013, 116 eligible patients were enrolled with VLR WT; negative lymph node sampling was required and predisposition syndromes were excluded. All cases had central review of pathology, diagnostic imaging and surgical reports on the AREN03B2 biology and classification study. Evaluable tumors were analyzed for mutation of WT1, 1p and 16q loss of heterozygosity (LOH) using microsatellite analysis, 1q gain, 1p and 16q loss by MLPA, and 11p15 loss o...