iPSC Neurons From Adult Survivors of Childhood Cancer Who Have Persistent Vincristine-Induced Neuropathy

Participants will be recruited from an existing protocol at St. Jude (SJLIFE, NCT00760656). Complete neuropathic evaluations are obtained as part of SJLIFE, and the information will be shared for use in the SJLPSC study. A one-time blood draw will be obtained, and peripheral blood mononuclear cells (PBMC's) will be isolated for eventual creation of induced pluripotent stem cells (iPSC) that will be differentiated into human neurons. These human neurons will allow the investigators to functionally validate and further interrogate CEP72 genetic variants or variants in other genes that are associated with persistent (or acute) vincristine neuropathy using a "state of the art" cellular model of human neurons. Furthermore, creating neurons from patients at the extremes (highly sensitive to vincristine-induced neuropathy and matched controls) allows the study of differences at baseline and after treatment with vincristine. PRIMARY OBJECTIVE: * To establish induced pluripotent stem cells (iPSCs) from childhood cancer survivors who did or did not develop persistent treatment-induced peripheral neuropathy, from which to make human neurons to assess their sensitivity to vincristine and determine whether neurons from patients who developed neuropathy are more sensitive to vincristine or other neurotoxic chemotherapy. SECONDARY OBJECTIVE: * To evaluate the iPSC neurons made from patients with persistent treatment-related neuropathy and iPSC neurons from patients who did not develop neuropathy from the same treatment, for phenotypic difference prior to and after exposure to vincristine or other potentially neurotoxic medications.