title: Somatic copy-neutral loss of  heterozygosity and copy number abnormalities in Malaysian sporadic colorectal  carcinoma patients.
abstract: Colorectal  cancer is one of the most common cancers in many countries, including Malaysia.  The accumulation of genomic alterations is an important feature of colorectal  carcinogenesis. A better understanding of the molecular events underlying the  stages of colorectal carcinogenesis might be helpful in the detection and  management of the disease. We used a commercially available single-nucleotide  polymorphism genotyping array to detect both copy number abnormalities (CNAs)  and copy-neutral loss of heterozygosity (LOH) in sporadic colorectal  carcinomas. Matched tumor and normal tissues of 13 colorectal carcinomas  (Dukes' stages A-D) were analyzed using a 250K single nucleotide polymorphism  array. An additional assay was performed to determine the microsatellite  instability status by using the National Cancer Institute-recommended BAT-26  panel. In general, copy number gain (92.3%) was most common, followed by copy  number loss (53.8%) and copy-neutral LOH (46.2%). Frequent CNAs of gains and  losses were observed on chromosomes 7p, 8, 13q, 17p, 18q, and 20q, and  copy-neutral LOH was observed on chromosomes 2, 6, 12, 13q, 14q, 17, 20p, 19q,  and 22q. Even though genomic alterations are associated with colorectal cancer  progression, our results showed that DNA CNAs and copy-neutral LOH do not  reflect disease progression in at least 50% tumors. Copy-neutral LOH was  observed in both early and advanced tumors, which favors the involvement of  these genomic alterations in the early stages of tumor development.
authors: Human Genome Centre, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, Malaysia.
authors: Y Y
authors: YY
authors: Yam
authors: B P
authors: BP
authors: Hoh
authors: N H
authors: NH
authors: Othman
authors: S
authors: S
authors: Hassan
authors: M M
authors: MM
authors: Yahya
authors: Z
authors: Z
authors: Zakaria
authors: R
authors: R
authors: Ankathil
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D002869:Chromosome Aberrations; D015179:Colorectal Neoplasms / Q000235:genetics*; D056915:DNA Copy Number Variations; D018450:Disease Progression; D005260:Female; D005838:Genotype; D006801:Humans; D019656:Loss of Heterozygosity; D008296:Malaysia; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide