NF1 and plexiform neurofibroma: Storlazzi et al. using G-banding and fluorescence in situ hybridization analysis showed that somatic inactivation of NF-1 gene located on chromosome 17 through chromosomal translocation leads to increased and abnormal production of neurofibromin which regulates ras-mediated cell growth pathway leading to increased levels of activating proteins p21ras and p13 which causes cellular proliferation of Schwann cells associated with neurofibroma [11].