We observed a significant decrease in mRNA and protein levels of Trp53 (p53) and Rb1 in Rnf20 haploinsufficient MLE12 cells and lungs (Fig. 2j–m), suggesting that increased DNA damage and insufficient activation of key tumor suppressor pathways may contribute to the increased incidence of lung tumorigenesis upon Rnf20 depletion. This evidence concerns the gene RB1 and neoplasm.