Results of APC gene LOH analysis using five polymorphic markers

Tamara Cacev, Sanja Kapitanovic and Kresimir Pavelic

Division of Molecular Medicine, Ruder Bokovic Institute, Zagreb, Croatia

We examined 46 cases of human sporadic colon cancer and corresponding normal tissue samples to evaluate the loss of heterozygosity (LOH) at the APC gene loci. DNAs were used for PCR, RFLP, VNTR and LOH analysis. To analyze LOH at the APC gene loci we used five polymorphic markers: three RFLP intragenic markers (exon 11 RsaI, exon 15 MspI, and exon 15 AspHI) and two VNTR flanking markers (D5S409 and D5S433). The informativity for all three intragenic RFLP markers was 50.0 % (23 of 46 assayed), and 21.7 % of tumors (5 of 23 informative) demonstrated LOH. The informativity for VNTR flanking markers D5S409 and D5S433 was 60.9 % (28 of 46 asseyed) and 87.0 % (40 of 46 asseyed) respectively. Eight of 28 informative tumors (28.6 %) demonstrated LOH for marker D5S409, and 14 of 40 informative tumors (35.0%) demonstrated LOH for marker D5S433. The informativity for all five APC loci was 100 % and 14 of 46 tumors ( 30.4 %) demonstrated LOH. Our study showed that it was necessary to use VNTR flanking markers D5S409 and D5S433 to increase the number of informative cases (from 50 % with intragenic markers) to 100 %. The highest informativity was observed for VNTR marker D5S433, 87 %.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Diagnostic Markers.