Adding to the CASeload: unwarranted p53 signaling induced by Cas9

We investigated the genetic and transcriptional changes associated with Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) associated protein 9 (Cas9) expression in human cancer cell lines. For a subset of cell lines with a wild-type tumor protein TP53 (best known as p53), we detected p53 pathway activation, DNA damage accumulation and emerging p53-inactivating mutations following Cas9 introduction. We discuss the potential implications of our findings in basic and translational research.