title: No evidence for mutation of B-RAF in urothelial carcinomas of the bladder and upper urinary tract.
abstract: Mutational activation of the MAP kinase pathway is frequently found in various cancers. Recently, activating mutations in the B-RAF gene, an important activator of this pathway, have been described in several tumor types including melanoma, colorectal and papillary thyroid cancer. The most frequent mutation in exon 15 (V599E), as well as several other mutations within exons 11 and 15 result in constitutive activation of the oncoprotein. In addition, a significant association between mismatch-repair (MMR) deficiency and the V599E mutation in colorectal tumors has been found. The aim of our study was to investigate B-RAF mutations in 121 urothelial carcinomas of the urinary bladder (ranging from pTaG1 to pT4aG3) and 27 tumors from the upper urinary tract (UUT), including 16 tumors of the renal pelvis and 11 tumors of the ureter). Twelve of 27 UUT tumors were MMR-deficient and showed microsatellite instability. The V599E mutation was screened for by allele-specific PCR (PASA) and exons 11 and 15 of B-RAF including intron-exon-boundaries were sequenced. Overall, 116/121 bladder tumors and 23/27 tumors of the UUT were successfully investigated by PASA. None of the tumors showed the V599E mutation. Sequence analysis of exons 11 and 15 was successful in 46 urothelial tumors (bladder, n=31; UUT, n=15). No mutations within the coding region of exons 11 and 15 and the intron-exon junctions were found. The most frequent alterations in the B-RAF gene do not seem to be involved in urothelial carcinogenesis, and there is no correlation between MMR-deficiency and B-RAF mutations in urothelial tumors.
authors.affiliation: Institute of Pathology, University of Regensburg, 93042 Regensburg, Germany. robert.stoehr@klinik.uni-regensburg.de
authors.forename: Robert
authors.initials: R
authors.lastname: Stoehr
authors.forename: Anke
authors.initials: A
authors.lastname: Brinkmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Filbeck
authors.forename: Christoph
authors.initials: C
authors.lastname: Gamper
authors.forename: Peter
authors.initials: P
authors.lastname: Wild
authors.forename: Hagen
authors.initials: H
authors.lastname: Blaszyk
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Hofstaedter
authors.forename: Ruth
authors.initials: R
authors.lastname: Knuechel
authors.forename: Arndt
authors.initials: A
authors.lastname: Hartmann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001483:Base Sequence; D002295:Carcinoma, Transitional Cell / Q000235:genetics / Q000473:pathology*; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D005091:Exons / Q000235:genetics; D005260:Female; D019073:HT29 Cells; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf; D019908:Proto-Oncogene Proteins c-raf / Q000235:genetics*; D014516:Ureteral Neoplasms / Q000235:genetics* / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D004273:DNA, Neoplasm; D017346:Protein Serine-Threonine Kinases; D048493:Proto-Oncogene Proteins B-raf; D019908:Proto-Oncogene Proteins c-raf