PARP1 and cancer: Among the 36 “radiogenes”, ATM, BRCA1/2, CHEK1, CCND1, MSH2, NBN, PARP1, PLK1, PRKDC, and RNF8, which are consistently up-regulated across the radioresistant cancer cell lines (Table 1) and the corresponding cancer tissue (Supplementary Figure 2), are crucially implicated in different stages of DDR/R.