Importantly, we detected the recombination event associated with Cre-mediated deletion of the Brca1 alelle (20 kb) in one tumor but we did not detect the deletions associated with recombination of the Cdh1 (14 kb), Trp53 (8 kb) or Brca2 (7 kb) alleles. This evidence concerns the gene CDH1 and neoplasm.