[Characteristics of plasma DNA and its application for detection of K-ras gene mutation].
DNA diagnosis is useful and significant for clinical oncology, but its use is limited due to a difficulty in preparing tumor-derived DNA materials. To overcome this problem, we investigated the characterization of plasma DNA and it application to successfully detecting K-ras mutation at codon 12 in normal persons, hematopoietic neoplasms, and solid tumors. The range of plasma DNA in each group was 15.8 +/- 5.2 ng/ml, 43.3 +/- 29.8 ng/ml, and 26.8 +/- 17.0 ng/ml, respectively. The ranges in patients with solid tumor were gradually decreased to the normal level of around 15 ng/ml in 3 weeks postoperatively. Plasma DNAs consisted of about 200 bp DNA fragmentation and were convenient for PCR amplification of K-ras gene. The mutation at codon 12 by PCR-RFLP analysis was detected in 13(27%) of 49 patients with solid tumors such as pancreatic cancer, breast cancer, colon cancer, and gastric cancer. The diagnostic specificity was 100%. Serial observations by the PCR-RFLP analysis revealed disappearance of the mutant K-ras about 7 days after successful curative surgery in a patient with gastric cancer.
Hayashi
T
T
Central Diagnostic Laboratory, Nagasaki University Hospital.
Sugahara
K
K
Dateki
N
N
Yamada
Y
Y
Sudou
R
R
Kanematsu
T
T
Kamihira
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003062:Codon / Q000235:genetics; D004247:DNA / Q000097:blood*; D004273:DNA, Neoplasm / Q000097:blood*; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis / Q000235:genetics; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012680:Sensitivity and Specificity
D003062:Codon; D004273:DNA, Neoplasm; D004247:DNA