ROS1 and cutaneous mastocytosis: Finally, a truncating variant in ROS1 (p.L1209X) was present in an individual who had CM, stomach, colorectal, merkel cell and thyroid cancers; ROS1 has been somatically mutated in gastric and colorectal tumours [50], as well as spitzoid and acral melanomas [51, 52]; however, germline variants in this gene have only been associated with myocardial infarction (by GWAS [53]), not cancer.