RESUMO
<p><b>OBJECTIVE</b>To refine the loss of heterozygosity (LOH) on chromosome 5p15 and screen new tumor suppressor gene(s) in colorectal tumorigenesis.</p><p><b>METHODS</b>Samples of colorectal cancer and normal tissue of 83 cases were collected in this study. Sixteen polymorphic microsatellite markers were analyzed on chromosome 5 and another 6 markers on chromosome 5p15 by PCR. PCR products were electrophoresed on an ABI 377 DNA sequencer. Genescan 3.1 and Genotype 2.1 software were used for LOH scanning and analysis.</p><p><b>RESULTS</b>Two distinct regions of frequent allelic deletions at D5S416 on 5p15 and D5S428-D5S410 on 5q were detected. Another 6 polymorphic microsatellite markers were applied to 5p15 and the minimal region of frequrent loss of heterozygosity was established on 5p15 spanning the D5S416 locus.</p><p><b>CONCLUSION</b>A critical and precise location of 5p deletions, 5p15.2-5p15.3, has been detected, which may contain one or more unknown tumor suppressor gene(s) related to colorectal cancer.</p>