Germline mutation in APC gene induced development of familial adenomatous polyposis (FAP). The risk of developing specific manifestation of FAP is often correlated with the position of the inherited APC mutation. Patients with mutations localized in the largest exon 15 between codons 1286 and 1513 (mutation cluster region, MCR) have generally a worse prognosis with early onset of the disease. We found 6 FAP families with mutation at codon 1309 (3927_3931delAAAGA) in the cohort of 39 FAP Slovak families with rapid cancer progress. In addition, mutation in codon 1309 was detected in three family members, one of them with a very different phenotype. This oldest family member, aged 81, has persisted asymptomatic without clinical manifestations.

Recombinant pMMEx-bovine leukemia virus env gene DNA fragments were produced and expressed in eukaryotic cells. Clone C4, containing an SmaI-SmaI fragment of the gene coding for gp51, was co-transfected with pSV2neo DNA into Chinese hamster cells. About 800 geneticin-resistant cell clones were isolated and then morphologically and biologically characterized. The presence of gp51 encoding env gene fragments was detected in 17 of them by Southern blotting. The expression of gp51 gene in hamster cells was confirmed by Western blotting of their lysates with monoclonal antibodies (MAbs) directed against different epitopes of gp51 of bovine leukemia virus. The immunoreactivity of the expressed peptides with MAbs directed against neutralizing epitopes of gp51 of bovine leukemia virus was confirmed.