Wyllie F S, Wynford-Thomas V, Lemoine N R, Williams G T, Williams E D, Wynford-Thomas D
Department of Pathology, University of Wales College of Medicine, Heath Park, Cardiff, UK.
Br J Cancer. 1988 Feb;57(2):135-8. doi: 10.1038/bjc.1988.28.
The possibility of an association between restriction fragment length polymorphisms (RFLPs) at the Ha-ras gene locus and susceptibility to develop colorectal cancer has been investigated. Leucocyte DNA from 46 carcinoma patients and 49 controls was analysed by Southern blotting to determine the size distribution of restriction fragments containing the variable tandem repeat 3' to the Ha-ras gene. Four predominant allelic fragments were found in both groups (in AvaII digests having sizes of 1.55, 2.0, 2.65 and 3.15 kilobases [kb]), together with a variety of 'rare' alleles (with individual frequencies less than 5%). The overall prevalence of rare alleles was not significantly different between cancer and control groups. The distribution of the common alleles, however, differed significantly. The combined frequency of the two larger alleles (a3 and a4) was approximately twice as high in the cancer group (34%) as in controls (18%) (P less than 0.025), which was reflected in a highly significant increase in the proportion of individuals carrying an a3 or a4 allele.
已对Ha-ras基因位点的限制性片段长度多态性（RFLP）与患结直肠癌易感性之间的关联可能性进行了研究。通过Southern印迹法分析了46例癌症患者和49例对照的白细胞DNA，以确定包含Ha-ras基因3'端可变串联重复序列的限制性片段的大小分布。在两组中均发现了四个主要等位基因片段（在AvaII消化物中大小分别为1.55、2.0、2.65和3.15千碱基[kb]），以及多种“稀有”等位基因（个体频率小于5%）。癌症组和对照组中稀有等位基因的总体流行率无显著差异。然而，常见等位基因的分布存在显著差异。两个较大等位基因（a3和a4）的合并频率在癌症组中（34%）约为对照组（18%）的两倍（P<0.025），这反映在携带a3或a4等位基因的个体比例显著增加。
