ALK and neuroblastoma: For this reason, we generated and characterized two independent Alk mutations (AlkY1355S and AlkF1251L) in Drosophila, for which the human orthologs (ALKY1278S and ALKF1174L) have previously been characterized as ‘gain-of-function’ mutations in neuroblastoma patients (Chand et al., 2013; Guan et al., 2017).