Shi C Y, Phang T W, Ngoi S S, Wee A, Li B, Lin Y, Lee H P, Ong C N
Department of Community, Occupational and Family Medicine, National University of Singapore, Kent Ridge.
Anticancer Res. 1994 Nov-Dec;14(6B):2811-6.
A series of colorectal carcinomas from an Asian population in Singapore were analyzed for mutations in the tumor suppressor gene p53. Based on single-strand conformation polymorphism (PCR-SSCP) analysis and direct DNA sequencing, 15 of 38 tumors (39%) were found to contain mutations in exons 5-8 of the p53 gene. The point mutations were predominantly base transitions. Among the 10 transitions, 5 were at CpG dinucleotide sites. One-third (5/15) of the mutations were found at previously identified hotspot codons 175, 248 and 282. In one case, an insertion of a 6-base pair sequence was found. p53 mutations did not correlate with tumor histological grade, Dukes' stage, or metastases. However, tumors at the distal site showed a higher proportion of mutations than the proximal site. Further, no mutation was found in the normal mucosa adjacent to tumor site, suggesting that no germ-line mutations were present. The results were compared with those from other studies and are discussed in connection to possible etiological factors that are specific to the local population.
对新加坡亚洲人群中的一系列结肠直肠癌进行了肿瘤抑制基因p53突变分析。基于单链构象多态性（PCR-SSCP）分析和直接DNA测序，在38个肿瘤中有15个（39%）被发现p53基因外显子5-8存在突变。点突变主要是碱基转换。在10个转换中，有5个位于CpG二核苷酸位点。三分之一（5/15）的突变发生在先前确定的热点密码子175、248和282处。在1例中，发现了一个6碱基对序列的插入。p53突变与肿瘤组织学分级、Dukes分期或转移无关。然而，远端部位的肿瘤比近端部位显示出更高的突变比例。此外，在肿瘤部位相邻的正常黏膜中未发现突变，这表明不存在种系突变。将结果与其他研究结果进行了比较，并结合当地人群特有的可能病因进行了讨论。
