While the most common example of this in our data is KRAS mutations in colorectal (lack of benefit for cetuximab) and lung cancer (lack of benefit for EGFR inhibitors), there is also growing evidence to support testing for acquired resistance mutations in ALK for example, where clinical benefit from newer second and third generation ALK inhibitors for NSCLC differs based on the specific mutation identified [28]. The gene discussed is ALK; the disease is non-small cell lung carcinoma.