CNTN2 and plexiform neurofibroma: J.E. Green also reported that transgenic tumor cells in HTLV-1 tax Tg mice expressed nerve growth factor [39], and other research groups showed that three other lines of tax Tg mouse had neurofibromas that had the potential to activate granulocyte-macrophage colony-stimulating factor [40,41], indicating that tax transgenic mice have a phenotype that may be different from the usual SS phenotype.