When the Food and Drug Agency (FDA) approved the Vysis ALK Break Apart FISH Probe Kit as the tool to detect ALK translocation in patients with advanced NSCLC, a cutoff to meet the criteria for ALK-positive was established: ≥15% of tumor cells demonstrating a pattern of ALK probe hybridization indicative of gene rearrangement [58,59]. Here, ALK is linked to non-small cell lung carcinoma.