NF1 and neoplasm: Combined Nf1/Trp53 inactivation, yielded tumors with a mean latency of 68 days, 100% penetrance and 86% bilateral tumor fraction, exceeding the efficiency of the previously reported CRISPR-mediated somatic mouse model of combined Nf1/Trp53 inactivation, which exhibited a median latency of ~100 days12.