Cancer is a not a single disease, but rather a collection of diseases caused by a wide range of molecular lesions (or mutations), both common and rare, and is not amenable to a “one size fits all” therapeutic approach. It is critical to identify the specific driving genetic mutation(s) in an individual’s tumor so targeted therapies can be pursued in a rational fashion. Advances in genome sequencing technology have made it possible to pinpoint the drivers of cancer in a personalized fashion.
One important class of mutation, called gene fusions, is a common cause of blood cancers. The prototypic example is the “BCR-ABL” gene fusion, characteristic of certain types of leukemia. Importantly, this finding led to the development of imatinib mesylate (Gleevec), which successfully targets the BCR-ABL gene fusion. Ninety-five percent of patients treated with this drug go into remission.
More recently, it was established that gene fusions, in addition to being the cause of blood cancers, may also play a key role in the development of common solid tumors such as prostate, lung, colon, and breast cancer. Thus, development of drugs targeting cancer-associated gene fusions will have a profound impact in the personalized therapy of a wide variety of cancer types.