Detection of K-ras mutations in stools of patients with colorectal cancer by mutant-enriched PCR.
Mutant-enriched PCR was applied to the detection of mutations at codons 12 and 13 of K-ras genes in the stools of patients with colorectal cancer. Mutations were analyzed in stool samples obtained prior to surgery. Resected tumor specimens were screened for K-ras mutations by PCR-mediated RFLP analysis. Using normal stool samples, assay conditions were adjusted to optimal sensitivity and specificity. The following specimens were included in the study: 16 stool samples corresponding to carcinomas in which K-ras mutations had been identified; 7 randomly selected stool samples corresponding to carcinomas which were negative for K-ras mutations; 1 stool sample from a patient with non-Hodgkin's lymphoma. In 13 of the 16 stool samples (81%) corresponding to tumors in which K-ras mutations had been identified previously, K-ras mutations were detected. In 2 of the 7 stool samples corresponding to tumors in which K-ras mutations had not been detected by previous PCR-mediated RFLP analysis, K-ras mutations were also present. Reanalyses of the tumors corresponding to these 2 positive stool samples by mutant-enriched PCR revealed a K-ras mutation in one of the tumors. The stool and tumor of the patient with non-Hodgkins lymphoma were negative for K-ras mutations. DNA sequence analysis revealed that, for each of the K-ras mutations identified in stool samples, identical base substitutions were present in the corresponding tumor tissue. The results indicate that tumor cells harboring K-ras mutations can be detected in the stools of patients with colorectal cancer by mutant-enriched PCR with high sensitivity and specificity. Because of the simplicity of the technique, it may be suitable for screening of stool samples for mutations of the K-ras gene.
Nollau
P
P
Abteilung für Klinische Chemie, Medizinische Klinik, Universitätskrankenhaus Eppendorf, Hamburg, Germany.
Moser
C
C
Weinland
G
G
Wagener
C
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D002460:Cell Line; D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D004252:DNA Mutational Analysis; D017931:DNA Primers; D005243:Feces; D005260:Female; D011905:Genes, ras; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009367:Neoplasm Staging; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D012150:Polymorphism, Restriction Fragment Length; D012016:Reference Values; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured
D003062:Codon; D017931:DNA Primers