Copy number of the Adenomatous Polyposis Coli gene is not always neutral in sporadic colorectal cancers with loss of heterozygosity for the gene

BMC Cancer

Research Article

Peter Zauber¹  Stephen Marotta²  Marlene Sabbath-Solitare² 

[1] Department of Medicine, Saint Barnabas Medical Center, 22 Old Short Hills Road, 07039, Livingston, NJ, USA;Department of Pathology, Saint Barnabas Medical Center, 100 Old Short Hills Road, 07039, Livingston, NJ, USA;

关键词: Genetic mutations;    Chromosomal number;    Colon tumors;    Loss of genetic material;    APC;    KRAS;   

DOI  :  10.1186/s12885-016-2243-z

 received in 2015-05-26, accepted in 2016-03-01,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundChanges in the number of alleles of a chromosome may have an impact upon gene expression. Loss of heterozygosity (LOH) indicates that one allele of a gene has been lost, and knowing the exact copy number of the gene would indicate whether duplication of the remaining allele has occurred. We were interested to determine the copy number of the Adenomatous Polyposis Coli (APC) gene in sporadic colorectal cancers with LOH.MethodsWe selected 38 carcinomas with LOH for the APC gene region of chromosome 5, as determined by amplification of the CA repeat region within the D5S346 loci. The copy number status of APC was ascertained using the SALSA® MLPA® P043-B1 APC Kit. LOH for the DCC gene, KRAS gene mutation, and microsatellite instability were also evaluated for each tumor, utilizing standard polymerase chain reaction methods.ResultsNo tumor demonstrated microsatellite instability. LOH of the DCC gene was also present in 33 of 36 (91.7 %) informative tumors. A KRAS gene mutation was present in 16 of the 38 (42.1 %) tumors. Twenty-four (63.2 %) of the tumors were copy number neutral, 10 (26.3 %) tumors demonstrated major loss, while two (5.3 %) showed partial loss. Two tumors (5.3 %) had copy number gain.ConclusionsResults of APC and DCC LOH, KRAS and microsatellite instability indicate our colorectal cancer cases were typical of sporadic cancers following the ‘chromosomal instability’ pathway. The majority of our colorectal carcinomas with LOH for APC gene are copy number neutral. However, one-third of our cases showed copy number loss, suggesting that duplication of the remaining allele is not required for the development of a colorectal carcinoma.

【 授权许可】

CC BY   
© Zauber et al. 2016