SEMIAUTOMATED ASSESSMENT OF LOSS OF HETEROZYGOSITY AND REPLICATION ERROR IN TUMORS

Loss of heterozygosity (LOH) and replication error (RER) are important phenomena in tumor development, with diagnostic and prognostic releva nce. Therefore, screening for LOH and RER is a desirable first step in the molecular analysis of tumors, We used semiautomated procedures ba sed on multicolor fluorescently labeled microsatellite markers and an automated sequencer for PCR amplification, electrophoresis of PCR prod ucts, and allele detection with a set of 16 microsatellites in 56 colo rectal tumors, We improved existing software for computer-assisted ass essment of LOH and RER, A comparison of these results with those of a conventional, radioactive technique and visual interpretation shows a high degree of correlation between the two methods. The detection rate s of LOH and RER are similar to those reported previously. The main ad vantages of the semiautomated fluorescence-based typing are in the obj ective, observer-unrelated, easy, and rapid computer-based scoring, an d the resulting quantitative assessment of RER.