癌组织中的遗传不稳定性的RAPD分析(简报)

肿瘤仍然是导致人类死亡的重要原因,由于缺乏深刻了解癌症的发生机制,尽管在过去25年中肿瘤的诊断和治疗都取得很大的进展,但肿瘤病人的存活率并没有显著的提高。目前有很多癌基因和抑癌基因如P16、P53、P73、ras、DCC和RB等

GENETIC INSTABILITY IN CANCER TISSUES NALYZED BY RAPD PCR

In five kinds of tumors, total 128 specimens were analyzed by RAPD (random amplified polymorphic DNA) PCR with nine 10-base arbitrary primers for detecting instabilities of DNA and chromosome and screening new molecular markers coupled to putative or unknown onco-genes and/or tumor suppressor genes. Bands representing instabilities have been recovered and purified from agarose and cloned into pCAPs vector, and further labeled by DIG as probes for analysis of Southern blot , Northern blot and Sequencing. Results revealed that sample 5 and 3 of the gastric cancers showed the highest genomic changes and the average detectability in five sorts of cancers was up to at least 40% (42. 2% - 49. 4% ) , and that there were significant differences in the ability of each primer to detect genomic instability,which ranged from 27% to 68% . Despite the highest detectability of genetic instability (68%) in tumor tissues , primer 2 could produce stable profiles of DNA bands in normal tissue genome with good reproducibility . On the contrary, primer 8 was of the lowest one (27 % ) . Band B of single copy found to be al-lelic losses in gastric and colon cancers according to RFLP analysis was of a novel sequence and registered by Gen-Bank ( Accession Number AF151005) .Therefore the genetic instabilities often concentrated on some special locus-es of chromosome e. g. repetitive sequences etc. and coupled to carcinogenesis . 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.