PAK1 and neoplasm: By 10 weeks of age when 100% of mice have tumours in the small intestine, the tumour incidence (i.e. the percentage of the number of mice having tumours in the small intestine (or colon and rectum) in the total number of mice observed) was also decreased in the small intestine of PAK1 het APC∆14/+ mice and PAK1 KO APC∆14/+ mice (Fig. 2b).