Genetic instability in cancer tissues analyzed by random amplified polymorphic DNA PCR.
OBJECTIVE
To detect DNA and chromosomes instabilities during the progression of tumors and screen new molecular markers coupled to putative or unknown oncogenes and/or tumor suppressor genes.


METHODS
Five kinds of tumors, in a total of 128 specimens, were analyzed by random amplified polymorphic DNA (RAPD) PCR. Bands representing instabilities were recovered, purified, and cloned, labeled as probes for Southern and Northern blot analysis and DNA sequencing.


RESULTS
Sample 5 and 3 of the gastric cancer tissues showed the highest genomic changes and the average detectability in five cancers was up to at least 40% (42.2% - 49.4%). There were significant differences in the ability of each primer to detect genomic instability, which ranged from 27% (primer 8) to 68% (primer 2). Band B is a single copy fragment, and was found to be an allelic loss in gastric and colon cancers. It is a novel sequence and was registered in GenBank with Accession Number AF151005. Further analysis revealed that it might be part of a cis-regulatory element of a new tumor suppressor gene, containing a promoter of cis-action "CACA" box, an enhancer of "GATA" family and a start codon.


CONCLUSIONS
It was impossible or difficult to get great achievements for cancer treatments with the procedure of gene therapy only to one oncogene or one tumor suppressor gene because the extensive DNA variations occurred during the progression of tumor. RAPD assay connected with other techniques was a good tool for the detection of genomic instabilities and direct screening of some new molecular markers related to tumor suppressor genes or oncogenes.
Wang
Jianxun
J
Department of Central Laboratory, First Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China. wang_jianxun@163.net
Wang
Qianwen
Q
Ye
Feng
F
D001483:Base Sequence; D015139:Blotting, Southern; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000473:pathology; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology; D012150:Polymorphism, Restriction Fragment Length; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology