These histological data—together with the finding that tumors induced by AAV-K, but not Lenti-KrasG12D, on the MMTV-Wnt1 background displayed high histological similarities to spontaneous tumors arising in noninfected MMTV-Wnt1 transgenic mice—provide another evidence that AAV-introduced CRISPR precision editing mimics natural tumor evolution more closely than virus-introduced ectopic expression of oncogenes. The gene discussed is WNT1; the disease is neoplasm.