Homozygous deletions may be markers of nearby heterozygous mutations: The complex deletion at FRA16D in the HCT116 colon cancer cell line removes exons of WWOX.
Amber E Alsop, Karen Taylor, Jieqing Zhang, Hani Gabra, Adam JW Paige, Paul AW Edwards
Genes Chromosomes Cancer | Published : 2008
Homozygous deletions in cancer cells have been thought to harbor tumor suppressor genes. We show that the 25 and 50 kb homozygous deletions in WWOX in the colon cancer cell line HCT116 result from a complex set of heterozygous deletions, some of which overlap to give homozygous loss. One of the heterozygous deletions has removed exons 6-8 of one allele of WWOX, and there is also a third copy of the distal region of WWOX in an unbalanced translocation. The exon 6-8 deletion results in allele-specific expression of a deleted transcript, which seems likely to be the main biological consequence of the deletions, since similar transcripts are found in other tumors. We show that such a complex set..View full abstract