Nevertheless, the lack of any recurrent gross alteration in the genome of dNFs favors the idea that, genetically, NF1 inactivation in neurofibroma-initiating cells (precursor cells that have the capacity to differentiate into Schwann cells) might be sufficient for dermal neurofibromas to develop (in an NF1 (+/−) background). This evidence concerns the gene NF1 and plexiform neurofibroma.