Taken together, these cross-species results further support Smad4 as potential target of chr 18 loss in the adenoma to colorectal carcinoma transition and highlight how synteny must be considered in cross-species analyses of aneuploidy, given the differing genomic arrangement of two of the most frequently altered TSGs (Apc and Smad4) in human colorectal carcinoma. The gene discussed is APC; the disease is adenoma.