Microdissection and polymerase chain reaction amplification of genomic DNA from histological tissue sections.

Polymerase chain reaction (PCR)-based assays are being used increasingly to study the molecular genetic changes that occur in minute cellular lesions that are identified in histological sections. It is often desirable to microdissect the cells of interest in a lesion, isolating them from surrounding normal tissue to obtain the purest representation of genomic DNA possible. We present here an optimized microdissection and DNA extraction protocol that reliably produces PCR-amplifiable DNA from lesional tissue less than 0.1 mm in diameter. The utility of this technique is demonstrated by PCR amplification and sequencing of the K-ras gene and microsatellite PCR analysis of proliferative epithelial lesions in the small ducts of a human pancreas involved by cancer.