OBJECTIVES: Polymorphism in the adenomatous polyposis coli (APC) gene was analyzed in 33 families suspected of familial adenomatous polyposis (FAP) without identified APC gene mutation. Screening of 104 members of mentioned families for polymorphism in the APC gene, was performed using single strand conformation polymorphism (SSCP) and DNA sequencing.
RESULTS: Twelve different types of polymorphism were found in the cohort of the families analyzed. Nine polymorphisms were located within exon 15, one within exon 6, one within exon 11 and one within exon 13. Of the 12 polymorphisms, 11 were silent substitution and only one was responsible for the amino acid change - D1822V, which was identified in 60% of the families analyzed.
CONCLUSION: The most frequently detected polymorphism D1822V is potentially associated with the risk of colorectal cancer. Three detected polymorphisms - Y486Y, T1493T and S1756S - also seem to be associated with colon cancer risk. All these polymorphisms may be used as markers for diagnosis of colorectal cancer. The importance of other detected polymorphisms remains still unclear, but their involvement is being continuously observed.