Monoclonal antibody Hb3: A marker for colon cancer progression or as a therapeutic target?

There are a number of researchers who are searching for useful tumor markers to indicate cure. Antigens are being applied as an effective target in clinical therapy. Hb3 is an anti-colorectal cancer monoclonal antibody produced in the researchers¡¯ laboratory, and whose sensitivity and specificity are superior to that of anti-CEA. Previous results have showed that CA-Hb3 may be useful in the clinical diagnosis of colorectal cancer.

This study, carried out by a team led by Professor G. C. Li, is described in a research article that will be published on March 14, 2008, in the World Journal of Gastroenterology.

To comprehensively identify the proteins of the tumor-associated antigen Ca-Hb3 which is recognized by colorectal carcinoma monoclonal antibody Hb3, Ca-Hb3 was isolated by SDS-PAGE followed by digestion with trypsin. The trypsin peptides were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Applying bioinformatics to analyze the proteins which were identified by mass spectrometry, Ca-Hb3 was identified as CKAP4-similar protein by nano-HPLC tandem mass spectrometry analysis. The molecular weight of CKAP4-similar protein is 62.02 kDa, including one hydrophobic region, one transmembrane domain, five coiled coils, four glycosylation sites and forty-nine phosphorylation sites. CKAP4-similar protein has high homogeneity with ¦¤Np63¦Á, and the characteristic expression of agrNp63 alpha that is considered a potential oncogene in the isoforms of p63 is similar to Ca-Hb3.

¦¤Np63¦Á is an isoform of the p63 family. A number of studies have highlighted the oncogenic potential of agrNp63 alpha.agrNp63 alpha is overexpressed in several epithelial cancers, often as a result of gene amplification. The overexpression of an Np63¦Á isoform in Rat 1A cells increases colony growth in soft agar and xenograft tumor formation in nude mice. It is hypothesized that agrNp63 alpha promotes survival and the maintenance of proliferative capacity in both epithelial stem cells and cancer cells.

Reference: Sun S, Guo FJ, Tong YQ, Zhu JG, Li GC. Research on colorectal carcinoma associated antigen Ca-Hb3 by one-dimensional PAGE and liquid chromatography-tandem mass spectrometry. World J Gastroenterol 2008; 14(10): 1588-1591
http://www.wjgnet.com/1007-9327/14/1588.asp

Correspondence to: Guan-Cheng Li, Professor, Cancer Research Institute, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha 410078, Hunan Province, China. libsun@public.cs.hn.cn

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 for providing 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 day 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 name of China National Journal of New Gastroenterology on October 1, 1995, and renamed WJG on January 25, 1998.

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