TP53 and neoplasm: Therefore, to assess functional roles for Irf7 and Irf8 in p53EPS formation, we used a transient CRISPR/Cas9 gene targeting approach to knock down irf7 or irf8 genes prior to p53EPS tumor formation using co-injection of two to three guide RNAs (gRNAs) each targeting irf7 or irf8 (Supplementary file 7), together with Cas9 protein and linearized EPS into one-cell stage tp53-/- embryos.