MICRODISSECTION AND POLYMERASE CHAIN-REACTION AMPLIFICATION OF GENOMIC DNA FROM HISTOLOGICAL TISSUE-SECTIONS

Polymerase chain reaction (PCR)-based assays are being used increasing ly to study the molecular genetic changes that occur in minute cellula r lesions that are identified iii histological sections. It is often d esirable to microdissect the cells of interest in a lesion, isolating them from surrounding normal tissue to obtain the purest representatio n of genomic DNA possible. We present here an optimized microdissectio n and DNA extraction protocol that reliably produces PCR-amplifiable D NA from lesional tissue less than 0.1 mm in diameter. The utility of t his technique is demonstrated by PCR amplification and sequencing of t he K-ras gene and microsatellite PCR analysis of proliferative epithel ial lesions in the small ducts of a human pancreas involved by cancer.