BACKGROUND: The Raf/MEK/ERK (mitogen activated protein kinase-MAPK) signal transduction cascade is an important mediator of a number of cellular fates, including growth, proliferation, and survival. The BRAF gene, one of the human isoforms of RAF, is activated by oncogenic Ras, leading to cooperative effects in cells responding to growth factor signals. AIMS: The aim of this study was to elucidate a possible function of BRAF in liver tumours. METHODS: Mutations of BRAF and KRAS were evaluated in 25 hepatocellular carcinomas (HCC) and in 69 cholangiocarcinomas (CC) by direct DNA sequencing analyses after microdissection. The presence of active intermediates of the MAPK pathway was assessed immunohistochemically. The results obtained were correlated with histopathological variables and patient survival. RESULTS: Activating BRAF missense mutations were identified in 15/69 CC (22%) and in one case of tumour surrounding liver. KRAS mutations were found in 31 of 69 (45%) CC examined and in two cases of tumour surrounding non-neoplastic liver tissue. In HCC, neither BRAF nor KRAS mutations were detected. All 31 CC with KRAS mutations had an intact BRAF gene. We failed to observe a correlation between BRAF or KRAS mutations and histopathological factors or prognosis of patients. CONCLUSIONS: Our data indicate that BRAF gene mutations are a relatively common event in CC but not in HCC. Disruption of the Raf/MEK/ERK (MAPK) kinase pathway, either by RAS or BRAF mutation, was detected in approximately 62% of all CC and is therefore one of the most frequent defects in cholangiocellular carcinogenesis.
BACKGROUND: The Raf/MEK/ERK (mitogen activated protein kinase-MAPK) signal transduction cascade is an important mediator of a number of cellular fates, including growth, proliferation, and survival. The BRAF gene, one of the human isoforms of RAF, is activated by oncogenic Ras, leading to cooperative effects in cells responding to growth factor signals. AIMS: The aim of this study was to elucidate a possible function of BRAF in liver tumours. METHODS: Mutations of BRAF and KRAS were evaluated in 25 hepatocellular carcinomas (HCC) and in 69 cholangiocarcinomas (CC) by direct DNA sequencing analyses after microdissection. The presence of active intermediates of the MAPK pathway was assessed immunohistochemically. The results obtained were correlated with histopathological variables and patient survival. RESULTS: Activating BRAF missense mutations were identified in 15/69 CC (22%) and in one case of tumour surrounding liver. KRAS mutations were found in 31 of 69 (45%) CC examined and in two cases of tumour surrounding non-neoplastic liver tissue. In HCC, neither BRAF nor KRAS mutations were detected. All 31 CC with KRAS mutations had an intact BRAF gene. We failed to observe a correlation between BRAF or KRAS mutations and histopathological factors or prognosis of patients. CONCLUSIONS: Our data indicate that BRAF gene mutations are a relatively common event in CC but not in HCC. Disruption of the Raf/MEK/ERK (MAPK) kinase pathway, either by RAS or BRAF mutation, was detected in approximately 62% of all CC and is therefore one of the most frequent defects in cholangiocellular carcinogenesis.
Authors: Mohamed-Ali Hakimi; Daniel A Bochar; Josh Chenoweth; William S Lane; Gail Mandel; Ramin Shiekhattar Journal: Proc Natl Acad Sci U S A Date: 2002-05-28 Impact factor: 11.205
Authors: A Tannapfel; M Wasner; K Krause; F Geissler; A Katalinic; J Hauss; J Mössner; K Engeland; C Wittekind Journal: J Natl Cancer Inst Date: 1999-07-07 Impact factor: 13.506
Authors: Harith Rajagopalan; Alberto Bardelli; Christoph Lengauer; Kenneth W Kinzler; Bert Vogelstein; Victor E Velculescu Journal: Nature Date: 2002-08-29 Impact factor: 49.962
Authors: Helen Davies; Graham R Bignell; Charles Cox; Philip Stephens; Sarah Edkins; Sheila Clegg; Jon Teague; Hayley Woffendin; Mathew J Garnett; William Bottomley; Neil Davis; Ed Dicks; Rebecca Ewing; Yvonne Floyd; Kristian Gray; Sarah Hall; Rachel Hawes; Jaime Hughes; Vivian Kosmidou; Andrew Menzies; Catherine Mould; Adrian Parker; Claire Stevens; Stephen Watt; Steven Hooper; Rebecca Wilson; Hiran Jayatilake; Barry A Gusterson; Colin Cooper; Janet Shipley; Darren Hargrave; Katherine Pritchard-Jones; Norman Maitland; Georgia Chenevix-Trench; Gregory J Riggins; Darell D Bigner; Giuseppe Palmieri; Antonio Cossu; Adrienne Flanagan; Andrew Nicholson; Judy W C Ho; Suet Y Leung; Siu T Yuen; Barbara L Weber; Hilliard F Seigler; Timothy L Darrow; Hugh Paterson; Richard Marais; Christopher J Marshall; Richard Wooster; Michael R Stratton; P Andrew Futreal Journal: Nature Date: 2002-06-09 Impact factor: 49.962
Authors: Bert H O'Neil; Laura W Goff; John Sae Wook Kauh; Jonathan R Strosberg; Tanios S Bekaii-Saab; Ruey-Min Lee; Aslamuzzaman Kazi; Dominic T Moore; Maria Learoyd; Richard M Lush; Said M Sebti; Daniel M Sullivan Journal: J Clin Oncol Date: 2011-04-25 Impact factor: 44.544
Authors: Tanios Bekaii-Saab; Mitch A Phelps; Xiaobai Li; Motoyasu Saji; Laura Goff; John Sae Wook Kauh; Bert H O'Neil; Stephanie Balsom; Catherine Balint; Ryan Liersemann; Vasily V Vasko; Mark Bloomston; William Marsh; L Austin Doyle; Gilian Ellison; Michael Grever; Matthew D Ringel; Miguel A Villalona-Calero Journal: J Clin Oncol Date: 2011-04-25 Impact factor: 44.544