Based on our original hypotheses and the inventory of samples, our specific aims were 1) to evaluate whether baseline/four-month plasma OPN levels were prognostic for EFS, RFS, bone or non-bone RFS and OS; 2) to evaluate whether primary tumor OPN IHC levels were prognostic for EFS, RFS, bone or non-bone RFS and OS; 3) to explore whether tumor OPN expression was associated with baseline plasma OPN levels; 4) to explore individual patient changes in plasma OPN from baseline/4 months to recurrence. The gene discussed is SPP1; the disease is neoplasm.