Farr C J, Saiki R K, Erlich H A, McCormick F, Marshall C J
Institute of Cancer Research, Royal Cancer Hospital, Chester Beatty Laboratories, London, England.
Proc Natl Acad Sci U S A. 1988 Mar;85(5):1629-33. doi: 10.1073/pnas.85.5.1629.
In vitro DNA amplification followed by oligonucleotide dot blot analysis were used to study RAS gene mutations in acute myeloid leukemia (AML). Fifty-two presentation AML DNAs were screened for mutations in codons 12, 13, and 61 of NRAS and in codons 12 and 61 of KRAS and HRAS. Fourteen (27%) contained mutations--all in NRAS and predominantly in codon 12. The most common amino acid substitution identified was of glycine by aspartic acid at codon 12 (7/18), with a G----A transition being the most common base change (11/18). No particular correlation was observed between disease subtype and the incidence or type of NRAS mutation. In DNA samples from four patients, 2 NRAS mutations were found to coexist. NIH 3T3 focus-formation assays revealed that in each case the mutations were present in different NRAS alleles. We also report the absence of a mutated RAS gene in relapse DNAs of four patients in which a RAS oncogene had been detected at presentation. These observations suggest that RAS mutations arise as part of the evolution of neoplastic transformation.
采用体外DNA扩增后进行寡核苷酸斑点印迹分析的方法，研究急性髓系白血病（AML）中的RAS基因突变情况。对52份初诊AML的DNA样本进行筛查，检测NRAS基因第12、13和61密码子以及KRAS和HRAS基因第12和61密码子的突变情况。14份样本（27%）含有突变——均为NRAS基因突变，且主要位于第12密码子。所鉴定出的最常见氨基酸替代是第12密码子处的甘氨酸被天冬氨酸替代（7/18），最常见的碱基变化是G→A转换（11/18）。未观察到疾病亚型与NRAS突变发生率或类型之间存在特定相关性。在4例患者的DNA样本中，发现存在2种NRAS突变共存的情况。NIH 3T3细胞集落形成试验表明，每种情况下这些突变存在于不同的NRAS等位基因中。我们还报告了4例初诊时检测到RAS癌基因的患者复发DNA中未发现RAS基因突变。这些观察结果提示，RAS基因突变是肿瘤转化演变过程的一部分。
