This study proposes to treat patients with the combination of sorafenib and irinotecan. Patients with relapsed, recurrent, refractory, or high risk malignancies whose tumors possess a non-synonymous mutation in Raf, PDGFR, VEGFR, Flt-3, KIT, JAK, STAT, RAS, MEK, or ERK will be eligible for the study. Very few phase 2 clinical trials have been performed in pediatrics using targeted agents in combination with conventional chemotherapy agents. Furthermore, since some combinations such as the combination of this study (sorafenib and irinotecan) have shown additive/synergistic effects in preclinical studies, therapy selecting for those patients who possess mutations targeted by the TKI of the study, may unveil activity that has not been previously observed. Thus, the investigators hope to determine whether the addition of additive/synergistic chemotherapy will increase efficacy of the targeted agent and/or increase tumor susceptibility to the targeted agent, resulting in increased anti-tumor activity.