The most notable protein kinases involved in fusions include the MAST kinases in breast cancer [81], present in 3 to 5% of cases, as well as RET in various cancers (particularly lung and thyroid) [76,82,83,84] and other RTKs in a variety of tumors [36,36,85,86,87,88,89,90,91,92,93,94,95,96,97]. The gene discussed is RET; the disease is cancer.