DETECTION OF MICROSATELLITE INSTABILITY IN CANCERS BY ARBITRARILY PRIMED PCR FINGERPRINTING USING A FLUORESCENTLY LABELED PRIMER (FAP-PCR)

The microsatellite mutator phenotype (MMP), detected as a change in th e number of repeating units in hundreds of thousands of microsatellite sequences in the tumor cell genome, underlies the carcinogenesis of a variety of tumors including sporadic and hereditary nonpolyposis colo n cancers. This enhanced microsatellite instability was discovered usi ng arbitrarily primed polymerase chain reaction (AP-PCR) fingerprintin g of DNA from colon cancers. In this study, we found an arbitrary prim er that can amplify multiple DNA fragments containing repeated sequenc es, including the poly A tracts found in the Alu repeats of the human genome. The combined use of primer labeling with fluorescence and an a utomated DNA sequencing analysis of AP-PCR products (FAP-PCR) detected alterations in fingerprint bands in all DNA samples previously determ ined to belong to the MMP. Fluorescent AP-PCR fingerprinting using thi s single arbitrary primer provides a convenient and efficient method f or detecting tumor specific fingerprint alterations that are usually u ndetectable by conventional fingerprinting.