The genetics of sarcomas segregate into two major types: those with specific genetic alterations and usually simple karyotypes, including fusion genes due to reciprocal translocations (e.g., PAX3‐FKHR in alveolar rhabdomyosarcomas) or specific point mutations (e.g., c‐kit mutations in gastrointestinal stromal tumors), and those with nonspecific genetic alterations and complex, unbalanced karyotypes, reflected by numerous genetic losses and gains (e.g., osteosarcoma, MFH, liposarcomas other than the myxoid type, angiosarcoma, leiomyosarcoma). The gene discussed is KIT; the disease is gastrointestinal stromal tumor.