DELETION MAPPING DEFINES DIFFERENT REGIONS IN 1P34.2-PTER THAT MAY HARBOR GENETIC INFORMATION RELATED TO HUMAN COLORECTAL-CANCER

Cytogenetic and molecular analyses of colorectal cancer cells have rev ealed deletions at 1p as prominent alterations, suggesting that geneti c information on the short arm of chromosome 1 has a role in tumorigen esis. In this study we have used 33 microsatellite markers to fine map deletions at 1p in primary colorectal carcinomas. We found 1p-deletio ns in 84% of the cases (31/37). High frequencies of loss of heterozygo sity (LOH), often the result of small independent interstitial deletio ns in the same tumor, defined three regions, that may harbor genetic i nformation relevant for colorectal cancer: (i) region A between D1S243 and D1S468 (7cM; 1p36.3); (ii) region B between D1S436 and D1S199 (7c M; 1p35.1-36.31) and (iii) region C between D1S496 and D1S255 (1cM; 1p 34.2-35). In addition we identified seven cell lines with LOH at 1p, a ll of which have deletions that span at least from the distal border o f region A to the proximal border of region C.