Laser-based microdissection technologies have been recently developed and applied to procure homogenous populations of tumor cells from paraffin-embedded and frozen tissue sections. When combined with whole-genomic amplification techniques, sufficient amounts of DNA can be generated from a small number of tumor cells procured by laser-based microdissection. Amplified DNA can then be used to perform high-throughput genome-wide allelotyping using fluorescent-labeled microsatellite markers spanning the whole genome. Loss of heterozygosity can be assessed by Genescan and Genotyper software (ABI Prism).