Stoehr Robert, Brinkmann Anke, Filbeck Thomas, Gamper Christoph, Wild Peter, Blaszyk Hagen, Hofstaedter Ferdinand, Knuechel Ruth, Hartmann Arndt
Institute of Pathology, University of Regensburg, 93042 Regensburg, Germany.
Oncol Rep. 2004 Jan;11(1):137-41.
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.
丝裂原活化蛋白激酶(MAP)激酶途径的突变激活在各种癌症中经常被发现。最近,该途径的重要激活剂B-RAF基因中的激活突变已在包括黑色素瘤、结直肠癌和甲状腺乳头状癌在内的几种肿瘤类型中被描述。外显子15中最常见的突变(V599E)以及外显子11和15内的其他几种突变导致癌蛋白的组成性激活。此外,在结直肠肿瘤中发现错配修复(MMR)缺陷与V599E突变之间存在显著关联。我们研究的目的是调查121例膀胱尿路上皮癌(范围从pTaG1到pT4aG3)和27例上尿路(UUT)肿瘤中的B-RAF突变,其中包括16例肾盂肿瘤和11例输尿管肿瘤。27例UUT肿瘤中有12例MMR缺陷并表现出微卫星不稳定性。通过等位基因特异性PCR(PASA)筛选V599E突变,并对B-RAF的外显子11和15(包括内含子-外显子边界)进行测序。总体而言,121例膀胱肿瘤中的116例和UUT的27例肿瘤中的23例通过PASA成功进行了研究。没有肿瘤显示V599E突变。外显子11和15的序列分析在46例尿路上皮肿瘤(膀胱,n = 31;UUT,n = 15)中成功完成。在外显子11和15的编码区域以及内含子-外显子连接处未发现突变。B-RAF基因中最常见的改变似乎不参与尿路上皮癌的发生,并且在尿路上皮肿瘤中MMR缺陷与B-RAF突变之间没有相关性。