title: KLF6 and TP53 mutations are a rare event in prostate cancer: distinguishing between Taq polymerase artifacts and true mutations.
abstract: Krüppel-like factor 6 (KLF6) has been reported to act as a tumor suppressor gene involved in the regulation of the cell cycle by activating p21 in a p53-independent manner. Many studies suggest that KLF6 is inactivated by allelic loss and somatic mutation. However, there is a high variability in the reported frequency of mutations (from 1 to 55%). TP53 also regulates the cell cycle through the activation of p21. In prostate cancer, the reported frequency of TP53 mutations ranges from 3 to 42%. In all these reports, there is a considerable degree of methodological heterogeneity. Our aim was to determine the frequency of KLF6 and TP53 mutations in a well-defined group of prostate tumors with different stages and Gleason grades. The four exons of KLF6 and exons 4-9 of TP53 were studied in 103 cases, including 90 formalin-fixed, paraffin-embedded (FFPE) and 13 frozen samples. All tumors were analyzed through PCR and direct sequencing. All changes found were confirmed by a second independent PCR and sequencing reaction. For KLF6, mutation (E227G) was only detected in one tumor (1%) and for TP53, three different mutations (L130H, H214R, and Y234C) were detected in five tumors (5%). This low mutation index is in keeping with recent papers on the subject. Our study strongly supports the notion that KLF6 and TP53 mutations are not frequent events in prostate cancer. When using FFPE tissues, it is mandatory to perform at least two independent rounds of PCR and sequencing to confirm mutations and exclude Taq polymerase-induced artifacts.
authors.affiliation: Department of Pathology, Hospital del Mar, Barcelona, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Agell
authors.forename: Silvia
authors.initials: S
authors.lastname: Hernández
authors.forename: Silvia
authors.initials: S
authors.lastname: de Muga
authors.forename: José A
authors.initials: JA
authors.lastname: Lorente
authors.forename: Núria
authors.initials: N
authors.lastname: Juanpere
authors.forename: Raquel
authors.initials: R
authors.lastname: Esgueva
authors.forename: Sergi
authors.initials: S
authors.lastname: Serrano
authors.forename: Antoni
authors.initials: A
authors.lastname: Gelabert
authors.forename: Josep
authors.initials: J
authors.lastname: Lloreta
mesh_terms: D016477:Artifacts; D001483:Base Sequence; D004252:DNA Mutational Analysis / Q000379:methods / Q000592:standards; D005557:Formaldehyde; D006801:Humans; D000075723:Kruppel-Like Factor 6; D051741:Kruppel-Like Transcription Factors / Q000235:genetics*; D008297:Male; D009154:Mutation; D016612:Paraffin Embedding; D016133:Polymerase Chain Reaction / Q000379:methods* / Q000592:standards; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019914:Taq Polymerase; D016707:Tissue Fixation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
chemical_list: C105465:KLF6 protein, human; D000075723:Kruppel-Like Factor 6; D051741:Kruppel-Like Transcription Factors; D011518:Proto-Oncogene Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D005557:Formaldehyde; D019914:Taq Polymerase