<qa>  What is the PI3 kinase pathway?Inhibitors of the PI3 kinase pathway have demonstrated preclinical activity in neuroblastoma. This activity may derive in part from destabilizing Mycn protein, impeding tumor angiogenesis, andor other effects. SF1126 is a novel inhibitor of PI3 kinase and mTOR that includes an active moiety consisting of LY294002 linked to an RGDS tetrapeptide that targets the active agent to integrin expressing tissues. In preclinical studies, SF1126 results in marked concentration of LY294002 into tumors. In an adult phase 1 trial, a maximum tolerated dose of SF1126 was not identified up to doses of 1110 mgm2 administered intravenously twice weekly on a continuous schedule. In this first pediatric phase 1 trial of SF1126, dose escalation will follow a 33 dose escalation design. Once a recommended phase 2 pediatric dose is identified, an expansion cohort of 10 patients with tumors with MYCN amplification, Mycn expression, or Myc expression will be treated. All patients will participate in mandatory pharmacokinetic testing. Additional optional correlative studies will evaluate potential predictive markers and potential pharmacodynamic markers, including PTEN and PIK3CA aberrations, Myc Mycn expression, and Myc pS6 levels in peripheral blood mononuclear cells. 