MYCN and neuroblastoma: On the other hand, a luciferase assay of the ALK-expressing doxycycline-inducible system (either wt ALK or mutated ALK) in PC12 and NB cell lines revealed that activation of ALK results in the increased initiation of transcription activity in the MYCN promoter region, suggesting MYCN as a putative downstream target of ALK-mediated signaling [16].