As ALKAL2 mutations have not been described in NB previously, the ALKAL2S53L variant was evaluated in PC12 cells by neurite outgrowth activity assay.14,28-30 Cotransfection of ALKAL2S53L with ALK results in neurite outgrowth at levels comparable with wild-type ALKAL2 (Fig 3A), indicating sustained ability to activate ALK. Here, ALK is linked to neuroblastoma.