In the middle and distal small intestine, CPC;Apcfl/fl;Klk6fl/fl mice had significantly fewer adenomas than CPC;Apcfl/fl;Klk6+/+ mice (p = 0.03 and p = 0.02, respectively), while no significant difference was observed in the number of adenomas between the CPC;Apcfl/fl;Klk6+/+ and CPC;Apcfl/fl;Klk6+/fl mice (p = 0.86 and p = 0.87, respectively). This evidence concerns the gene KLK6 and adenoma.