Recently, microRNAs from tumor cells have been detected circulating in the blood of patients with cancer. This presents a novel opportunity to assess the utility of microRNAs in the blood as an early predictor of cancer as well as a marker of response to therapy. No previous studies have been performed evaluating microRNAs in archived tumor tissue and blood of patients with Neurofibromatosis type 1 (NF-1). The investigators propose a feasibility study to evaluate the presence of microRNAs in archived tumor tissue and the blood of patients with NF-1. If the investigators are able to identify circulating microRNAs in this population of pediatric patients, they will build upon this data in proposing a future study.