Thirteen fluorescent labeled polymorphic microsatellite markers were analyzed in 83 cases of colorectal carcinoma and matched normal tissue DNA by polymerase chain reaction (PCR). PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.7 and Genotype 3.7 software were used for loss of heterozygosity (LOH) scanning and analysis. Compared with clinicopathological features, significant relationship was observed between LOH frequencies on D4S3018 locus. In tumor larger than 5 cm in diameter, LOH frequency was significantly higher than that less than 5 cm (56% vs13.79%, P = 0.01). On D4S1534 locus, LOH was significantly associated with liver metastasis (80% vs 17.25%, P = 0.012).

A research article to be published on September 28, 2008 in the World Journal of Gastroenterology addresses this question. The research team led by Prof. Zheng from Department of Abdomen Surgery Department, the Affiliated Yantai Yuhuangding Hospital of Qingdao University Medical College, expressed that tumor suppressor genes may exist on 4q in sporadic colorectal carcinoma.

The classic mechanism of tumor suppressor gene (TSG) inactivation is described by two-hit modes in which one allele is mutated (or promoter hypermethylation or a small intragenic deletion) and the other allele is lost through a number of possible mechanisms, resulting in LOH at multiple loci.

LOH is the most common molecular genetic alteration observed in human cancers. A great deal of evidence supported the presence of TSGs in the short arm of chromosome 4. Much less studies have been reported in colorectal cancer. By deletion dense markers mapping, they detected two obvious high frequency LOH regions (4q12-21.1 and 4q25-31.1). PTPN13 (4q21.3), Caspase3 (4q34) and caspase6 (4q24-35), T1A12/mac25 (4q12-13) genes are putative TSGs.

This is a report that describes the LOH events on 4q in sporadic CRC in Chinese patients, further studies will benefit from this paper. The data presented is clear and concise in the text.

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Reference: Jiang LX, Xu J, Wang ZW, Li DP, Peng ZH, Gao JJ, He L, Zheng HT. Tumor suppress genes screening analysis on 4q in sporadic colorectal carcinoma.World J Gastroenterol 2008; 14(36): 5606-5611

About World Journal of Gastroenterology

World Journal of Gastroenterology (WJG), a leading international journal in gastroenterology and hepatology, has established a reputation for publishing first class research on esophageal cancer, gastric cancer, liver cancer, viral hepatitis, colorectal cancer, and H pylori infection. It provides a forum for both clinicians and scientists. WJG has been indexed and abstracted in Current Contents/Clinical Medicine, Science Citation Index Expanded (also known as SciSearch) and Journal Citation Reports/Science Edition, Index Medicus, MEDLINE and PubMed, Chemical Abstracts, EMBASE/Excerpta Medica, Abstracts Journals, Nature Clinical Practice Gastroenterology and Hepatology, CAB Abstracts and Global Health. ISI JCR 2003-2000 IF: 3.318, 2.532, 1.445 and 0.993. WJG is a weekly journal published by WJG Press. The publication dates are the 7th, 14th, 21st, and 28th of every month. The WJG is supported by The National Natural Science Foundation of China, No. 30224801 and No. 30424812, and was founded with the title China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.

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