In addition to correlating very well with FISH negative and positive results, dichotomous immunohistochemical reactivity (0 vs 3+) with the ALK antibody seems to represent the strongest predictor of response to ALK inhibitor therapy,[39] In fact, FISH-negative IHC-positive non-small cell lung cancer was repeatedly shown to respond to ALK-inhibitor therapy, while FISH-positive IHC-negative tumors failed treatment in 100% of cases.[40–43]. This evidence concerns the gene ALK and non-small cell lung carcinoma.