PARP1 and cancer: The most frequently amplified genes across the Pan-Cancer Atlas were NBN (n = 4,275, 40.8%), EXO1 (n = 3,714, 35.4%), PARP1 (n = 3,695, 35.2%), PRKDC (n = 3,650, 34.8%) and POLB (n = 2,794, 26.6%) (Figure 1C).