Detection of codon 61 point mutations of the K-ras gene in lung and colorectal cancers by enriched PCR.
Mutation of the Kirsten ras (K-ras) gene is one of most common alterations in solid tumors including lung and colorectal cancers. We developed new enriched PCR-RFLP assay to detect mutations of K-ras codon 61 at the 1st and 2nd letters and non-enriched PCR-RFLP assay to detect the 3rd letter mutation. One mutant allele among 10(3) wild-type alleles was detected by enriched PCR-RFLP assay, while one mutant in 10 wild-type alleles was detected by non-enriched PCR-RFLP assay for codon 61 3rd letter. We then examined K-ras codon 12, 13 and 61 mutations in lung and colorectal cancers using these assays. K-ras codon 12 mutation was detected in 10 of 109 (9%) lung cancer and 19 of 83 (23%) colorectal cancer cases. K-ras codon 13 mutation was detected in 2 of 83 (2%) colorectal and 0 of 109 NSCLC cases, respectively. There was no K-ras codon 61 mutation in either type of cancer. Our results demonstrate that enriched PCR-RFLP is a sensitive assay to detect K-ras codon 61 mutation, however, it was extremely rare in lung and colorectal cancers, suggesting organ-specific pathways in mutagenesis of the ras gene family.
Toyooka
Shinichi
S
Department of Cancer and Thoracic Surgery, Graduate School of Medicine and Dentistry, Okayama University, Okayama 700-8558, Japan.
Tsukuda
Kazunori
K
Ouchida
Mamoru
M
Tanino
Motohiko
M
Inaki
Yasuhiko
Y
Kobayashi
Kazuyasu
K
Yano
Masaaki
M
Soh
Junichi
J
Kobatake
Takuya
T
Shimizu
Nobuyoshi
N
Shimizu
Kenji
K
D000368:Aged; D000483:Alleles; D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics*; D004247:DNA; D005091:Exons; D005260:Female; D011905:Genes, ras; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D012150:Polymorphism, Restriction Fragment Length
D003062:Codon; D004247:DNA