<prompt> The most impoant determinant of prognosis in Wilms tumorStage of diseaseLoss of heterozygosity of chromosome I pHistologyAge less than one year at presentation  <response>: The most impoant prognostic factors in Wilms tumor is its histopathology.3 of tumors show ourable pathologyfocal anaplasiafor which only surgical excision is needed.Another 6 have unourable pathologydiffuse analplasia;these tumors are pleomorphic and ruptured and show early metastasis to bones. Other prognostic factors are Stage of the disease,Ploidydiploid tumors have better prognosis than hyperdiploid tumors.Young age,low stage and low tumor weight550 g are ourable prognostic factors.Presence of anaplasia and loss of heterozygosity of 1p or 16q increase risk recurrence. Reference:Essential pediatrics-Ghai,8th edition,page no:618 