SEARCH · PubMed Health

Results for “BRAF”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

PubMed2026

Molecular Landscape and Advanced Diagnostic Technologies for BRAF Mutations in Cancer: From Quantitative PCR and ddPCR to CRISPR-Based Platforms.

BRAF mutations are key oncogenic alterations across multiple malignancies, including melanoma, thyroid carcinoma, colorectal cancer, non-small cell lung cancer, glioma, and hairy cell leukemia. The most prevalent variant, BRAF-V600E, induces constitutive activation of the MAPK signaling pathway, promoting tumor progression and influencing therapeutic responsiveness. Accurate detection of BRAF alterations is therefore essential for molecular classification, prognostic assessment, treatment selection, and resistance surveillance. This review summarizes the molecular heterogeneity of BRAF mutations and critically evaluates current diagnostic methodologies. Conventional approaches such as allele-specific PCR and Sanger sequencing are compared with advanced quantitative platforms, including high-resolution melting analysis, droplet digital PCR, and next-generation sequencing, with emphasis on analytical sensitivity, mutation coverage, and clinical applicability. Emerging technologies such as CRISPR-based assays, rolling circle amplification systems, and nanoparticle-based biosensors and point-of-care diagnostic platforms are also discussed for their potential to enhance ultra-sensitive detection, particularly in liquid biopsy settings. These emerging tools are highlighted for their potential to enable ultra-sensitive, rapid, and decentralized mutation detection, particularly in liquid biopsy settings. Key challenges, including intratumoral heterogeneity, low allele-frequency variants, FFPE-associated artifacts, and clonal evolution under therapeutic pressure, are examined within a translational framework. In addition, we examine critical barriers to clinical implementation, including standardization, cost, and global accessibility of molecular diagnostics, and outline potential solutions through scalable technologies and decentralized testing strategies. We propose that optimal BRAF testing requires a mutation subclass-informed and clinically integrated strategy combining comprehensive baseline profiling with longitudinal molecular monitoring. Future diagnostic paradigms will likely integrate multi-omics data and artificial intelligence (AI)-assisted interpretation to refine precision oncology implementation. Looking forward, we propose that optimal BRAF testing will require integration of multi-omics profiling with AI-assisted interpretation, enabling automated variant classification, real-time clinical decision support, and improved prediction of therapeutic response and resistance.

Humans↗

PubMed2026

Leptomeningeal Dissemination in TERT Promoter-mutant Anaplastic Pleomorphic Xanthoastrocytoma Responding to BRAF-MEK Inhibition: A Case Report.

Pleomorphic xanthoastrocytoma is a rare brain tumor that frequently harbors the oncogenic BRAF V600E mutation. Approximately 28.6%-47% of high-grade pleomorphic xanthoastrocytomas are associated with TERT promoter mutation and leptomeningeal dissemination, for which no established treatment exists and the prognosis remains poor. Combination therapy with BRAF and MEK inhibitors has demonstrated efficacy in BRAF V600E-mutant brain tumors. We report a case of a 22-year-old man with a right temporal lobe tumor initially diagnosed as World Health Organization grade 2 pleomorphic xanthoastrocytoma after gross total resection. Two years later, the tumor recurred and underwent malignant transformation to World Health Organization grade 3 pleomorphic xanthoastrocytoma. At the third resection, pathological and genomic analyses confirmed BRAF V600E mutation together with TERT promoter mutation. Following chemoradiotherapy, spinal leptomeningeal dissemination developed. After spinal irradiation, dabrafenib plus trametinib was initiated, resulting in partial radiological response and symptomatic improvement. Although regrowth occurred 10 months after initiation of targeted therapy, the patient remains alive at the time of writing. Here, we report a case of recurrent anaplastic BRAF V600E-mutant pleomorphic xanthoastrocytoma with leptomeningeal dissemination that showed a transient but clinically meaningful response to combined BRAF-MEK inhibition and spinal radiation therapy. In addition, this case raises the possibility of an association between TERT promoter mutation and leptomeningeal dissemination, although further studies are required to clarify this relationship.

BRAF V600E↗

PubMed2006

Analysis of differential BRAF(V600E) mutational status in multifocal papillary thyroid carcinoma: evidence of independent clonal origin in distinct tumor foci.

BACKGROUND: Papillary thyroid cancers often occur as multiple foci. Multifocal cancers have been considered to have a poor prognosis because they are thought to be the consequence of intrathyroidal spread of the papillary cancer. However, to the authors' knowledge there has been little investigation into whether multifocal thyroid papillary carcinomas arise from the intrathyroidal spread of a single carcinoma or from independent primary tumors. To answer this question, the BRAF(V600E) mutational status of individual tumor foci was examined. This approach was justified because in the Korean population a high proportion (65%) of papillary carcinomas harbor the BRAF mutation. METHODS: DNA was isolated from paraffin-embedded tissue samples of multifocal papillary thyroid carcinoma and the BRAF exon 15 was amplified by the polymerase chain reaction (PCR). The PCR product was digested with restriction endonuclease TspRI to test for the presence of the BRAF(V600E) (T1799A) mutation. RESULTS: In all, 140 cancers from 61 patients diagnosed with multifocal papillary carcinoma were examined. The BRAF mutation was found in all the individual cancers in 29 (47.5%) of the patients (all-positive group) and the mutation was absent in all the individual cancers in 8 (13.1%) patients (all-negative group). However, in 24 (39.3%) patients, some of the individual cancers contained the BRAF mutation, whereas others did not (mixed group). CONCLUSIONS: At least 39.3% of the multifocal papillary cancers in the Korean population that were examined could be attributed to independently arising papillary cancers rather than to intrathyroidal spread of single cancers.

Adult↗

PubMed2005

Exon 15 BRAF mutations are uncommon in canine oral malignant melanomas.

An activating mutation in codon 599 of BRAF has been identified in approximately 60% of human cutaneous nevi and melanomas, but not melanomas of mucosal origin. The purpose of this study was to determine if BRAF mutations occur in canine oral malignant melanomas. The canine BRAF gene was first cloned from normal canine testicular cDNA, and a novel previously unreported splice variant involving exon 5 was identified during this process. To screen canine melanoma samples for BRAF mutation in codon 599, cDNA and genomic DNA were isolated from canine malignant melanoma cell lines and primary tumor samples respectively, all from cases seen at the Veterinary Medical Teaching Hospital at the University of California, Davis. Polymerase chain reaction (PCR) was performed for exon 15 using primers based at the 5' end of exon 15 and the 5' end of intron 15 and the resultant products were directly sequenced. No mutations in codon 599 or exon 15 were identified in any of the 17 samples evaluated. However, all of the melanoma cell lines expressed BRAF and demonstrated high levels of basal ERK phosphorylation suggesting that dysregulation of this pathway is present. Therefore, similar to the case with human mucosal melanomas, canine oral malignant melanomas do not possess codon 599 BRAF mutations commonly identified in human cutaneous melanomas. This finding supports the notion that melanomas arising from non-sun-exposed sites exhibit distinct mechanisms of molecular transformation.

Amino Acid Sequence↗

PubMed2004

Both BRAF and KRAS mutations are rare in colorectal carcinomas from patients with hereditary nonpolyposis colorectal cancer.

The BRAF mutations have been suggested to be linked with defective mismatch repair in colorectal carcinomas. To clarify the extent of BRAF mutations in HNPCC colorectal carcinomas, which are typical mismatch repair deficient carcinomas, we compared the frequency of BRAF mutations between HNPCC, familial adenomatous polyposis (FAP) and sporadic cases. The frequency of KRAS mutations was also compared between these three syndromes. No BRAF mutations were detected in 33 HNPCC colorectal carcinomas, while they were detected in 3 of 26 (12%) FAP carcinomas and 2 of 53 (4%) microsatellite stable sporadic carcinomas. KRAS mutations were detected in 2 of 33 (6%) HNPCC, 9 of 26 (35%) FAP and 18 of 53 (34%) sporadic carcinomas. Such extremely low frequencies of BRAF and KRAS mutations in HNPCC colorectal carcinomas suggest that the participation of RAS-RAF signaling is minor in HNPCC, and that the previously suggested high frequency of BRAF mutations in mismatch repair deficient colorectal carcinomas is not due to mutations of mismatch repair genes.

Adenomatous Polyposis Coli↗

PubMed2006

BRAF and KRAS gene mutations in intraductal papillary mucinous neoplasm/carcinoma (IPMN/IPMC) of the pancreas.

The Raf/MEK/ERK (MAPK) signal transduction is an important mediator of a number of cellular fates including growth, proliferation, and survival. The BRAF gene is activated by oncogenic RAS, leading to cooperative effects in cells responding to growth factor signals. Our study was performed to elucidate a possible role of BRAF in the development of IPMN (Intraductal Papillary Mucinous Neoplasm) and IPMC (Intraductal Papillary Mucinous Carcinoma) of the pancreas. Mutations of BRAF and KRAS were evaluated in 36 IPMN/IPMC samples and two mucinous cystadenomas by direct genomic sequencing. Exons 1 for KRAS, and 5, 11, and 15 for BRAF were examined. Totally we identified 17 (47%) KRAS mutations in exon 1, codon 12 and one missense mutation (2.7%) within exon 15 of BRAF. The mutations appear to be somatic since the same alterations were not detected in the corresponding normal tissues. Our data provide evidence that oncogenic properties of BRAF contribute to the tumorigenesis of IPMN/IPMC, but at a lower frequency than KRAS.

Adenocarcinoma, Mucinous↗

PubMed2006

BRAF and c-kit gene copy number in mutation-positive malignant melanoma.

Activating mutations in BRAF or c-kit have been reported in malignant melanoma. Because the activating mutations are dominant, it has been assumed that they are heterozygous in the affected tumors. To test this, we have carefully examined the DNA sequencing electropherograms on 43 BRAF mutation-positive and 3 c-kit mutation-positive malignant melanomas to determine the ratio of the normal to mutant allele. Of the 43 BRAF mutation-positive tumors, we classified 26 as presumptive heterozygous. Eight cases were indeterminate. Surprisingly, 9 cases appeared to contain an excess of the mutant allele. BRAF fluorescence in situ hybridization on these 9 cases suggested the increased amount of the mutant BRAF allele was due to amplification (2 cases) or chromosome 7 polysomy (7 cases). We have previously described the presence of the c-kit-activating mutation, L576P, in 2 of 100 malignant melanomas. In this report, we have evaluated an additional 53 cases and found 1 additional case that contained the L576P mutation. Evaluation of the DNA sequencing electropherograms from all 3 cases of L576P mutation-positive melanoma suggests a selective loss of the normal allele. Fluorescence in situ hybridization for c-kit on these 3 L576P mutation-positive tumors indicated that one showed slight amplification of the c-kit gene and the other 2 were present in a nonamplified diploid state. These results have important implications concerning the mechanism of oncogenesis in melanoma as well as in the response of the tumor to anticancer drugs targeting BRAF or c-kit.

Base Sequence↗

PubMed2005

BRAF polymorphisms and the risk of ovarian cancer of low malignant potential.

OBJECTIVE: The object of this study was to test the hypothesis that BRAF is a low-risk susceptibility gene for low malignant potential (LMP) ovarian cancer. A recent study of the relationship between BRAF polymorphisms and malignant melanoma identified strong linkage disequilibrium across the BRAF gene with one of the three most common haplotypes (haplotype C) having a population attributable risk of approximately 1.6%. We therefore hypothesized that the same BRAF haplotype may confer an increased risk of serous ovarian tumors of low malignant potential. METHODS: We genotyped 383 cases of LMP ovarian cancer, including 234 of serous histology, and 987 controls for seven SNPs, representative of the most common BRAF gene haplotypes, using MALDI-TOF mass spectrometry. RESULTS: Haplotype information was obtained for 369 LMP ovarian cancer cases and 983 healthy controls. None of the haplotypes were found to be associated with risk of LMP ovarian cancer (OR for haplotype C 0.81, 95% CI = 0.54-1.22), or with the risk of serous LMP ovarian cancer (OR for haplotype C 0.90, 95% CI = 0.56-1.45). CONCLUSION: We found no evidence to suggest that BRAF is a low-risk LMP ovarian cancer susceptibility gene.

Adult↗

PubMed2005

BRAF mutations in aberrant crypt foci and hyperplastic polyposis.

Patients with hyperplastic polyposis have multiple hyperplastic polyps (HPs) and increased risk of colorectal carcinomas. Aberrant crypt foci (ACF) are postulated to be the earliest precursor lesions in colorectal carcinogenesis. We evaluated BRAF mutations by DNA sequencing in 53 ACF from patients with sporadic colorectal carcinomas and familial adenomatous polyposis, in 18 sporadic HPs from patients with resected colorectal cancer, and in 70 HPs, 4 serrated adenomas, 3 admixed hyperplastic-adenomatous polyps, 10 tubular adenomas, and 6 carcinomas from 17 patients with multiple/large HPs and/or hyperplastic polyposis. BRAF mutation status was compared with clinicopathological features and other genetic alterations by marginal logistic regression. BRAF mutation was present in only 2% of ACF and 6% of sporadic HPs. In contrast, BRAF mutation was present in 43% of HPs (P = 0.01 versus sporadic HPs), 75% of serrated adenomas, 33% of admixed hyperplastic-adenomatous polyps, 30% of tubular adenomas, and 33% of carcinomas from patients with multiple/large HPs and/or hyperplastic polyposis. BRAF mutation status in patients with multiple/large HPs and/or hyperplastic polyposis correlated with HPs from the same patient (odds ratio, 5.8; P = 0.0002) but associated with younger age (odds ratio, 0.83; P = 0.006 compared to older age), with a large HP (odds ratio, 22.5; P = 0.01 compared with patients with multiple HPs), with location of HPs in the right colon (odds ratio, 3.0; P = 0.03), and with methylation of the p16 gene and the MINT31 locus [odds ratio, 12.2 (P = 0.0001) and 4.4 (P = 0.02), respectively]. Our study shows that BRAF mutation status is heterogeneous among patients with multiple/large HPs and/or hyperplastic polyposis, suggesting differences in pathogenesis of HPs that indicate subsets within this phenotype.

Adenocarcinoma↗

PubMed2005

Mutational activation of BRAF is not a major event in sporadic childhood papillary thyroid carcinoma.

Papillary thyroid carcinoma may encompass a mixed group of neoplasms where divergence in clinical behavior may reflect distinct genetic alterations. For example, young patients with papillary thyroid carcinoma have a better prognosis than affected adults, and their carcinomas are much more likely to harbor chromosomal rearrangements involving the RET proto-oncogene. Mutational activation of the BRAF oncogene has recently been identified as the most common genetic alteration in papillary thyroid carcinoma, but little is known about its frequency as a function of patient age. We tested 20 papillary thyroid carcinomas from young patients ranging from 10 to 17 years of age for the thymine (T) --> adenine (A) missense mutation at nucleotide 1796 in the BRAF gene using a newly developed assay that employs a novel primer extension method (Mutector assay). The prevalence of BRAF mutation was compared with a larger group of papillary thyroid carcinomas from previously tested adult patients (>20 years). BRAF mutations were not common in papillary thyroid carcinomas from young patients compared to their counterparts in adults (20 vs 77%; OR=13.3, 95% confidence interval (CI)=3.4-56.5; P<0.0001), but they become increasingly prevalent with advancing patient age (OR as a function of age at 10-year intervals=1.80 CI=1.33-2.44; P<0.001). Unlike papillary thyroid carcinomas that arise in adults, mutational activation of BRAF is not a major genetic alteration in papillary thyroid carcinomas that arise in young patients. The increasing frequency of BRAF mutations as a function of age could help account for the well documented but poorly understood observation that age is a relevant prognostic indicator for patients with papillary thyroid carcinoma.

Adolescent↗

PubMed2006

BRAF mutations and phosphorylation status of mitogen-activated protein kinases in the development of flat and depressed-type colorectal neoplasias.

Although some molecular differences between flat-depressed neoplasias (FDNs) and protruding neoplasias (PNs) have been reported, it is uncertain if the BRAF mutations or the status of phosphorylated mitogen-activated protein kinase (p-MAPK) are different between theses two groups. We evaluated the incidence of BRAF and KRAS mutations, high-frequency microsatellite instability (MSI-H), and the immunohistochemical status of p-MAPK in the nonserrated neoplasias (46 FDNs and 57 PNs). BRAF mutations were detected in four FDNs (9%) and none of PNs (P=0.0369 by Fisher's exact test). KRAS mutations were observed in none of FDNs and in 14 PNs (25%; P=0.0002 by Fisher's exact test). MSI-H was detected in seven out of 44 FDNs (16%) and in one out of 52 of PNs (2%) (P=0.022 by Fisher's exact test). Type B and C immunostaining for p-MAPK was observed in 34 out of 46 FDNs (72%), compared with 24 out of 55 PNs (44%; P=0.0022 by chi(2) test). There was no significant difference in the type B and C immunostaining of p-MAPK between FDNs with and without BRAF mutations. BRAF and KRAS mutations are mutually exclusive in the morphological characteristics of colorectal nonserrated neoplasia. Abnormal accumulation of p-MAPK protein is more likely to be implicated in the tumorigenesis of FDNs than of PNs. However, this abnormality in FDNs might occur via the genetic alteration other than BRAF or KRAS mutation.

Adenocarcinoma↗

PubMed2006

Targeting BRAF in thyroid cancer.

Activating mutations in the gene encoding BRAF are the most commonly identified oncogenic abnormalities in papillary thyroid cancer. In vitro and in vivo models have demonstrated that overexpression of activated BRAF induces malignant transformation and aggressive tumour behaviour. BRAF and other RAF kinases are frequently activated by other thyroid oncogenes and are important mediators of their biological effects including dedifferentiation and proliferation. Because current therapeutic options for patients with thyroid cancers that are aggressive and/or do not respond to standard therapies are limited, BRAF and its downstream effectors represent attractive therapeutic targets. In this review, data supporting a role for BRAF activation in thyroid cancer development and establishing the potential therapeutic efficacy of BRAF-targeted agents in patients with thyroid cancer will be reviewed.

Enzyme Activation↗

PubMed2004

BRAF alterations are associated with complex mutational profiles in malignant melanoma.

To evaluate the mutational profiles associated with BRAF mutations in human melanoma, we have studied BRAF, RAS, PTEN, TP53, CDKN2A and CDK4 genes and their expression in melanoma lesions. Owing to the lack of sufficient material from fresh specimens, we employed short-term cell lines obtained from melanoma biopsies. In all, 41 melanoma obtained from eight primary lesions, 20 nodal, 11 cutaneous and two visceral metastases from patients with sporadic (n=31), familial (n=4) and multiple melanoma (n=2) were analysed. The results revealed novel missense mutations in the BRAF, PTEN, CDKN2A and CDK4 genes. Overall, activating mutations of BRAF and loss of functional p16 and ARF were detected in the majority of melanomas (29/41, 36/41 and 29/41, respectively), while PTEN alterations/loss, NRAS and TP53 mutations occurred less frequently (6/41, 6/41 and 10/41, respectively). In the resulting 12 mutational profiles, p16/ARF loss associated with mutated BRAFV599E was the most represented (n=15). In addition, TP53 and PTEN mutations were always accompanied with BRAF alterations, while PTEN loss was found in association with CDKN2A or TP53 mutations in the absence of BRAF activation. The p16/ARFDelta+BRAF/RAS profile was significantly associated with a longer survival, while complex mutational profiles were detected in highly aggressive disease and poor survival. These data support the existence of several molecularly defined melanoma groups which likely reflect different clinical/biological behaviour, thus suggesting that a more extensive molecular classification of melanoma would significantly impact its clinical management.

Adult↗

PubMed2004

Inhibition of growth and invasive ability of melanoma by inactivation of mutated BRAF with lentivirus-mediated RNA interference.

Oncogenic mutations of molecules involved in the mitogen-activated protein kinase (MAPK) pathways provide signals mediating both tumor growth and invasion in various cancers including melanomas. BRAF somatic mutations, found in 66% of melanomas, have NIH3T3 transforming ability with the elevated kinase activity in vitro. We attempted to mediate RNA interference (RNAi) with HIV lentiviral vectors specific for either wild type or the most frequently mutated form of BRAF (V599E) in 10 melanoma cell lines, and found that RNAi inhibited the growth of most melanoma cell lines in vitro as well as in vivo, which was accompanied by decrease of both BRAF protein and ERK phosphorylation. Interestingly, the mutated BRAF (V599E)-specific siRNA inhibited the growth and MAPK activity of only melanoma cell lines with this mutation. Furthermore, BRAF RNAi inhibited matrigel invasion of melanoma cells accompanied with a decrease of matrix metalloproteinase activity and beta(1) integrin expression. These results clarify that the mutated BRAF (V599E) is essentially involved in malignant phenotype of melanoma cells through the MAPK activation and is an attractive molecular target for melanoma treatment. The lentivirus-mediated RNAi specific for oncogenic mutations may be a powerful technique for gene therapy of cancer.

Cell Division↗

PubMed2006

Oncogenic BRAF regulates beta-Trcp expression and NF-kappaB activity in human melanoma cells.

Mutational activation of BRAF is a frequent event in human malignant melanomas suggesting that BRAF-dependent signaling is conducive to melanoma cell growth and survival. Previously published work reported that melanoma cells exhibit constitutive anti-apoptotic nuclear factor kappaB (NF-kappaB) transcription factor activation triggered by proteolysis of its inhibitor IkappaB. IkappaB degradation is dependent upon its phosphorylation by the IkappaB kinase (IKK) complex and subsequent ubiquitination facilitated by beta-Trcp E3 ubiquitin ligase. Here, we report that melanocytes expressing a conditionally oncogenic form of BRAF(V600E) exhibit enhanced beta-Trcp expression, increased IKK activity and a concomitant increase in the rate of IkappaBalpha degradation. Conversely, inhibition of BRAF signaling using either a broad-spectrum Raf inhibitor (BAY 43-9006) or by selective knock-down of BRAF(V600E) expression by RNA interference in human melanoma cells leads to decreased IKK activity and beta-Trcp expression, stabilization of IkappaB, inhibition of NF-kappaB transcriptional activity and sensitization of these cells to apoptosis. Taken together, these data support a model in which mutational activation of BRAF in human melanomas contributes to constitutive induction of NF-kappaB activity and to increased survival of melanoma cells.

Cell Line, Tumor↗

PubMed2004

Genetic interaction between NRAS and BRAF mutations and PTEN/MMAC1 inactivation in melanoma.

Extant evidence implicates growth factor signaling in the pathogenesis of many tumor types, including cutaneous melanoma. Recently, reciprocal activating mutations of NRAS and BRAF were found in benign melanocytic nevi and cutaneous melanomas. We had previously reported a similar epistatic relationship between activating NRAS mutations and inactivating PTEN/MMAC1 alterations. We thus hypothesized that BRAF and PTEN/MMAC1 mutations may cooperate to promote melanoma tumorigenesis. Overall, 40 of 47 (85%) melanoma cell lines and 11 of 16 (69%) uncultured melanoma metastases had mutations in NRAS, BRAF, or PTEN/MMAC1. NRAS was exclusively mutated in nine of 47 (19%) cell lines and two of 16 (13%) metastases, whereas BRAF was solely mutated in 28 of 47 (60%) cell lines and nine of 16 (56%) metastases. In the 12 of 15 melanoma cell lines (80%) and two of two melanoma metastases with PTEN alterations, BRAF was also mutated. These findings suggest the existence of possible cooperation between BRAF activation and PTEN loss in melanoma development.

Cell Line, Tumor↗

PubMed2006

BRAF mutation and AKAP9 expression in sporadic papillary thyroid carcinomas.

AIM: We aimed to determine the BRAF mutation and AKAP9 expression in papillary thyroid carcinomas (PTCs). METHODS AND RESULTS: In this study, we analysed 100 sporadic PTC specimens and we detected mutation in 62.2% of the conventional type PTCs (51/82), in 50% of the follicular variant type PTCs (3/6), in 50% of the diffuse sclerosing variant type PTCs (1/2), and in 30% of the microcarcinomas (3/10). All mutations involved a T-->A transversion at the nucleotide 1796. The cases with BRAF mutation were significantly associated with extrathyroidal extension. We also evaluated the expression of AKAP9 protein by immunohistochemistry. The AKAP9 protein was seen as a single perinuclear dot in all the PTCs. Therefore, 58% of the specimens harboured the BRAF mutation and no case had AKAP9-BRAF fusion in the sporadic PTCs. CONCLUSION: Our results suggest that the BRAF mutation can be a useful diagnostic and prognostic marker and a target for exploring novel cancer therapies to treat PTCs. AKAP9-BRAF fusion may be a very rare event in sporadic PTCs.

A Kinase Anchor Proteins↗

PubMed2006

The BRAF-MAPK signaling pathway is essential for cancer-immune evasion in human melanoma cells.

The mitogen-activated protein kinase (MAPK) pathway is frequently activated in human cancers, leading to malignant phenotypes such as autonomous cellular proliferation. Here, we demonstrate a novel role of the activated MAPK pathway in immune evasion by melanoma cells with the mutation of BRAF, which encodes a MAPKKs, (BRAF(V600E)). MEK inhibitor U0126 or RNA interference (RNAi) for BRAF(V600E) decreased production of the immunosuppressive soluble factors interleukin (IL)-10, VEGF, or IL-6 from melanoma cells to levels comparable to those after signal transducer and activator of transcription (STAT)3 inactivation. The suppressive activity of the culture supernatants from the melanoma cells on the production of inflammatory cytokines IL-12 and tumor necrosis factor alpha by dendritic cells upon lipopolysaccharide stimulation was markedly reduced after transduction with BRAF(V600E) RNAi, comparable to the effects observed with STAT3 RNAi transduction. No additive or synergistic effects were observed by the simultaneous transduction of RNAi for both BRAF(V600E) and STAT3. Furthermore, specific DNA binding and transcriptional activity of STAT3 were not affected by down-regulation of the MAPK signaling with the BRAF RNAi. These results indicate that the MAPK signal, along with the STAT3 signal, is essential for immune evasion by human melanomas that have constitutively active MAPK signaling and is a potential molecular target for overcoming melanoma cell evasion of the immune system.

Cell Line, Tumor↗