Deletion mapping reveals two regions of chromosome 8 allele loss in colorectal carcinomas
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Updated: Aug 8, 2026
Deficient Pms2, ERCC1, Ku86, CcOI in Field Defects During Progression to Colon Cancer
Published on: July 29, 2010
M L Yaremko1, M L Wasylyshyn, K L Paulus
1Department of Pathology, University of Chicago, Illinois.
Abstract:
Colorectal carcinogenesis is associated with the accumulation of genetic changes involving both dominant oncogenes and tumor suppressor genes. Although at least four different genes have been implicated in the process, the detection of allele loss from other regions of the genome suggests the involvement of additional genes. The short arm of chromosome 8 is one of these regions; loss of heterozygosity occurs at rates ranging from 30 to 50%. To define the region of common deletion containing the putative tumor suppressor gene, we analyzed a series of 87 carcinomas for allele loss in different regions of the short arm of chromosome 8 by using Southern blot analysis and a panel of polymorphic probes. We found allele loss in 33% of our cases, which involves two separate regions, one in the p-terminal region of the chromosome, 8p23.1-pter, where 45% of informative cases demonstrated loss, and the other in the mid-p region, at 8p21, where 31% of cases showed allele loss. No tumors showed loss of heterozygosity for both regions. These findings suggest the presence of two discrete genes related to colorectal carcinogenesis on the short arm of chromosome 8.
Insights
Genetic analysis of colorectal cancer reveals two distinct tumor suppressor genes on chromosome 8p. These findings advance our understanding of colorectal carcinogenesis and potential therapeutic targets.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Colorectal cancer (CRC) development involves accumulating genetic alterations in oncogenes and tumor suppressor genes.
- While several genes are implicated, allele loss in specific genomic regions suggests additional tumor suppressor genes are involved.
- Chromosome 8 short arm (8p) shows significant loss of heterozygosity (30-50%) in CRC, indicating a potential tumor suppressor locus.
Purpose of the Study:
- To pinpoint the common deletion region on chromosome 8p harboring a putative tumor suppressor gene.
- To investigate the specific locations and frequencies of allele loss on 8p in colorectal carcinomas.
Main Methods:
- Analysis of 87 colorectal carcinomas using Southern blot analysis.
- Utilized a panel of polymorphic probes to assess allele loss across different regions of chromosome 8p.
Main Results:
- Identified allele loss in 33% of the analyzed colorectal carcinomas.
- Two distinct regions of common deletion were found on 8p: 8p23.1-pter (45% loss) and 8p21 (31% loss).
- No tumors exhibited loss of heterozygosity in both identified regions, suggesting distinct genes.
Conclusions:
- The short arm of chromosome 8 harbors at least two separate tumor suppressor genes crucial for colorectal carcinogenesis.
- These findings provide a refined understanding of the genetic landscape of colorectal cancer and identify specific chromosomal regions for further investigation.
