title: Comparison of KRAS mutation tests in colorectal cancer patients.
abstract: The KRAS pathway and studies evaluating KRAS as a prognostic marker in colorectal cancer are discussed along with advances in KRAS gene mutation testing. Highly sensitive real-time polymerase chain reaction (PCR) methods were developed for this purpose. We examined the applicability of direct sequencing and two real-time PCR methods in the diagnosis of KRAS mutations. We used real-time PCR and direct sequencing-based methods to determine applicability of these KRAS mutation tests in 64 colorectal cancers. The two DNA samples found to be mutation positive by real-time PCR were analyzed again after diluting 100-fold. The results were the same. When we applied the same strategy for the direct sequencing, even a 10-fold dilution did not show the mutations. Therefore, we found that sequencing may not be informative when there are only a few mutant cells in the tumor. KRAS mutation screening on formalin-fixed, paraffin-embedded DNA is very efficient with real-time PCR methods in comparison to direct sequencing. The development and adoption of guidelines for KRAS mutation testing are crucial for success.
authors.affiliation: Department of Medical Biology and Genetics, Faculty of Medicine, Istanbul Bilim University, Istanbul, Turkey. vshancer@yahoo.com
authors.forename: Veysel Sabri
authors.initials: VS
authors.lastname: Hancer
authors.forename: Murat
authors.initials: M
authors.lastname: Buyukdogan
authors.forename: Ilknur
authors.initials: I
authors.lastname: Türkmen
authors.forename: Nuray
authors.initials: N
authors.lastname: Bassullu
authors.forename: Tuncay
authors.initials: T
authors.lastname: Altug
authors.forename: Reyhan
authors.initials: R
authors.lastname: Diz-Kucukkaya
authors.forename: Gulen
authors.initials: G
authors.lastname: Bulbul-Dogusoy
authors.forename: Gokhan
authors.initials: G
authors.lastname: Demir
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics*
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins