RESUMO
Posterior fossa group A (PFA) ependymoma is a lethal brain cancer diagnosed in infants and young children. The lack of driver events in the PFA linear genome led us to search its 3D genome for characteristic features. Here, we reconstructed 3D genomes from diverse childhood tumor types and uncovered a global topology in PFA that is highly reminiscent of stem and progenitor cells in a variety of human tissues. A remarkable feature exclusively present in PFA are type B ultra long-range interactions in PFAs (TULIPs), regions separated by great distances along the linear genome that interact with each other in the 3D nuclear space with surprising strength. TULIPs occur in all PFA samples and recur at predictable genomic coordinates, and their formation is induced by expression of EZHIP. The universality of TULIPs across PFA samples suggests a conservation of molecular principles that could be exploited therapeutically.
RESUMO
BACKGROUND: The MEK inhibitor, selumetinib, reduces plexiform neurofibroma (PN) in pediatric patients with neurofibromatosis type 1 (NF1). Its safety and efficacy in adults with PN and effectiveness in other NF1manifestations (e.g., neurocognitive function, growth reduction, and café-au-lait spots) are unknown. METHODS: This open-label, phase 2 trial enrolled 90 pediatric or adult NF1 patients with inoperable, symptomatic, or potentially morbid, measurable PN (≥ 3 cm). Selumetinib was administered at doses of 20 or 25 mg/m2 or 50 mg q 12 hrs for 2 years. Pharmacokinetics, PN volume, growth parameters, neurocognitive function, café-au-lait spots, and quality of life (QoL) were evaluated. RESULTS: Fifty-nine children and 30 adults (median age, 16 years; range, 3-47) received an average of 22±5 (4-26) cycles of selumetinib. Eighty-eight (98.9%) out of 89 per-protocol patients showed volume reduction in the target PN (median, 40.8%; 4.2%-92.2%), and 81 (91%) patients showed partial response (≥ 20% volume reduction). The response lasted until cycle 26. Scores of neurocognitive functions (verbal comprehension, perceptual reasoning, processing speed, and full-scale IQ) significantly improved in both pediatric and adult patients (P <0.05). Prepubertal patients showed increases in height score and growth velocity (P <0.05). Café-au-lait spot intensity decreased significantly (P <0.05). Improvements in QoL and pain scores were observed in both children and adults. All adverse events were CTCAE grade 1 or 2 and were successfully managed without drug discontinuation. CONCLUSION: Selumetinib decrease PN volume in the majority of pediatric and adult NF1 patients while also showing efficacy in non-malignant diverse NF1 manifestations.