ALK and neuroblastoma: Moreover, the ALK-mutated SH-SY5Y cell line displayed low proliferation, but the cell population appeared similar to SK-N-BE(2), indicating good adaptation to the imposed growth conditions, since SH-SY5Y presented a lower karyorrhexis index than SK-N-BE(2), which could be related to an increased frequency of ALK mutations at a relapse of neuroblastoma.