Infrequent loss of chromosomal heterozygosity in human stomach cancer.

By molecular genetic approach using polymorphic DNA markers which detect allelic deletion at specific chromosomal loci, we analyzed 30 human stomach cancers for possible loss of chromosomal heterozygosity. We analyzed 25 loci on 18 different chromosomes covering regions frequently deleted in several types of cancers. Loss of chromosomal heterozygosity was observed only in five of 30 cases examined, and it was infrequently detected at 10 loci on seven different chromosomes including chromosome 1 in two of 12 cases, chromosome 12 in one of four cases and chromosome 13 in three of 27 cases. It was also observed at loci on chromosomes 11, 14, 16, and 19 with very low frequency (less than 10%), but not on other chromosomes: chromosomes 3, 5, 6, 9, 10, 15, 17, 18, 20, and 22. Thus, in human stomach cancer, loss of heterozygosity occurs infrequently even at chromosomal loci often deleted in other types of cancers.