Although ALK fusions/rearrangements occur in ~3–7% of NSCLCs, ~50% of IMTs and 50–80% of ALCLs, such alterations are ultra-rare in other cancers, being found in only ~0.2% of patients, making studies in these diseases challenging, and perhaps below the feasibility threshold of prospective treatment trials, even those that are large scale such as NCI-MATCH and similar efforts192,193. Here, ALK is linked to cancer.