APC and neoplasm: Interestingly, we recently identified Tiam1 as a Wnt-responsive gene that is upregulated in intestinal and colon tumours, and by comparing tumour development in APC mutant multiple intestinal neoplasia (Min) mice expressing or lacking Tiam1, we found that Tiam1 deficiency significantly reduces the formation and growth of intestinal polyps in vivo (Malliri et al, 2006).