The induction of optimal systemic antitumor immunity involves the priming of both CD4+ and CD8+ T cells specific for tumor-associated antigens. The role of CD4+ T helper cells (Th) in this response has been largely attributed to providing regulatory signals required for the priming of major histocompatibility complex class I restricted CD8+ cytolytic T lymphocytes, which are thought to serve as the dominant effector cell mediating tumor killing. However, analysis of the effector phase of tumor rejection induced by vaccination with irradiated tumor cells transduced to secrete granulocyte/macrophage colony-stimulating factor indicates a far broader role for CD4+ T cells in orchestrating the host response to tumor. This form of immunization leads to the simultaneous induction of Th1 and Th2 responses, both of which are required for maximal systemic antitumor immunity. Cytokines produced by these CD4+ T cells activate eosinophils as well as macrophages that produce both superoxide and nitric oxide. Both of these cell types then collaborate within the site of tumor challenge to cause its destruction.

Juvenile myelomonocytic leukemia (JMML) is a myeloproliferative neoplasm (MPN) of childhood with a poor prognosis. Mutations in NF1, NRAS, KRAS, PTPN11 and CBL occur in 85% of patients, yet there are currently no risk stratification algorithms capable of predicting which patients will be refractory to conventional treatment and therefore be candidates for experimental therapies. In addition, there have been few other molecular pathways identified aside from the Ras/MAPK pathway to serve as the basis for such novel therapeutic strategies. We therefore sought to genomically characterize serial samples from patients at diagnosis through relapse and transformation to acute myeloid leukemia in order to expand our knowledge of the mutational spectrum in JMML. We identified recurrent mutations in genes involved in signal transduction, gene splicing, the polycomb repressive complex 2 (PRC2) and transcription. Importantly, the number of somatic alterations present at diagnosis appears to be the major determinant of outcome.

Important knowledge deficits exist among adult survivors of childhood cancer regarding basic aspects of their diagnosis and treatment. Such deficits could impair survivors' ability to seek and receive appropriate long-term follow-up care.