A Story of Swapped Ends

It was dubbed the “Philadelphia chromosome,” named after the city where the abnormal chromosome was first described in 1960 ( 1 ). Peter Nowell, of the University of Pennsylvania, and David Hungerford, at the Fox Chase Cancer Center, had taken a close look at patients with chronic myeloid leukemia (CML) and found that regardless of sex, they had a very small chromosome. It was a turning point in cancer biology—the beginning of a story that would draw new attention to chromosome abnormalities as a cause of cancer, a phenomenon that still influences our understanding of the disease.