For example Apcfl/fl and Apc580S/580S mice show reduced expression of Apc protein throughout their tissues (in the absence of Cre‐mediated recombination of alleles), and develop hepatocellular carcinomas between 9 and 15 months (our unpublished observations of Apc580S/580S mice; 63, 64). This evidence concerns the gene APC and hepatocellular carcinoma.