RAPID MICROSATELLITE ANALYSIS OF PARAFFIN-EMBEDDED TUMOR SPECIMENS FROM PATIENTS WITH HEREDITARY NONPOLYPOSIS COLORECTAL-CANCER

In screening for hereditary non-polyposis colorectal cancer (HNPCC)-an autosomal dominant disorder characterised by mutations in mismatch re pair genes-detection of microsatellite instability is an important dia gnostic criterion. The mono- or dinucleotide repeat DNA sequences are usually amplified from formalin fixed, paraffin embedded tissue by pol ymerase chain reaction after numerous time consuming steps including d eparaffinisation, DNA extraction, and purification. A rapid single ste p method for direct DNA analysis is described, based on preincubation of paraffin embedded tissue with Triton X-100 followed by DNA amplific ation with fluorescence labelled primers and electrophoresis in an aut omated sequencer. This procedure allows precise allele sizing and anal ysis of genetic instability, is more efficient and time saving, reduce s the risk of contamination, and is therefore of particular interest i n screening for HNPCC.