Prevalence of BRAF V600E mutation in Chinese melanoma patients: large scale analysis of BRAF and NRAS mutations in a 432-case cohort

Multiregional Sequencing Reveals Genomic Alterations and Clonal Dynamics in Primary Malignant Melanoma of the Esophagus

Primary malignant melanoma of the esophagus (PMME) is a rare and aggressive disease with high tendency of metastasis. To characterize the genetic basis and intratumor heterogeneity of PMME, we performed multiregion exome sequencing and whole genome SNP array genotyping of 12 samples obtained from a patient with PMME. High intratumor heterogeneity was observed in both somatic mutation and copy-number alteration levels. Nine geographically separate samples including two normal samples were clonally related and followed a branched evolution model. Most putative oncogenic drivers such as BRAF and KRAS mutations as well as CDKN2A biallelic inactivation were observed in trunk clones, whereas clinically actionable mutations such as PIK3CA and JAK1 mutations were detected in branch clones. Ancestor tumor clones evolved into three subclonal clades: clade1 fostered metastatic subclones that carried metastatic features of PIK3CA and ARHGAP26 point mutations as well as chr13 arm-level deletion, clade2 owned branch-specific JAK1 mutations and PTEN deletion, and clade3 was found in two vertical distribution samples below the primary tumor area, highlighting the fact that it is possible for PMME to disseminate by the submucosal longitudinal lymphatic route at an early stage of metastasis. These findings facilitate interpretation of the genetic essence of this rare melanoma subtype as well as the pattern of cancer evolution, thus reinforcing the therapeutic challenges associated with PMME.Significance: This study highlights the use of multiregion exome sequencing and whole genome SNP array genotyping to comprehensively characterize the genetic landscape of a rare type of esophogeal melanoma. Cancer Res; 78(2); 338-47. ©2017 AACR.

Frequent Genetic Aberrations in the CDK4 Pathway in Acral Melanoma Indicate the Potential for CDK4/6 Inhibitors in Targeted Therapy

Purpose: Effective therapies for the majority of metastatic acral melanoma patients have not been established. Thus, we investigated genetic aberrations of CDK4 pathway in acral melanoma and evaluated the efficacy of CDK4/6 inhibitors in targeted therapy of acral melanoma.Experimental Design: A total of 514 primary acral melanoma samples were examined for the copy number variations (CNV) of CDK4 pathway-related genes, including Cdk4, Ccnd1, and P16^INK4a , by QuantiGenePlex DNA Assay. The sensitivity of established acral melanoma cell lines and patient-derived xenograft (PDX) containing typical CDK4 aberrations to CDK4/6 inhibitors was evaluated.Results: Among the 514 samples, 203 cases, 137 cases, and 310 cases, respectively, showed Cdk4 gain (39.5%), Ccnd1 gain (26.7%), and P16^INK4a loss (60.3%). The overall frequency of acral melanomas that contain at least one aberration in Cdk4, Ccnd1, and P16^INK4a was 82.7%. The median overall survival time for acral melanoma patients with concurrent Cdk4 gain with P16^INK4a loss was significantly shorter than that for patients without such aberrations (P = 0.005). The pan-CDK inhibitor AT7519 and selective CDK4/6 inhibitor PD0332991 could inhibit the cell viability of acral melanoma cells and the tumor growth of PDX with Cdk4 gain plus Ccnd1 gain, Cdk4 gain plus P16^INK4a loss, and Ccnd1 gain plus P16^INK4a loss.Conclusions: Genetic aberration of CDK4 pathway is a frequent event in acral melanoma. Acral melanoma cell lines and PDX containing CDK4 pathway aberrations are sensitive to CDK4/6 inhibitors. Our study provides evidence for the testing of CDK4/6 inhibitors in acral melanoma patients. Clin Cancer Res; 23(22); 6946-57. ©2017 AACR.

Mutations in BRAF codons 594 and 596 predict good prognosis in melanoma

B-Raf proto-oncogene serine/threonine kinase (BRAF) V600E is the most common kinase-activating mutation and is associated with poor prognosis in melanoma. However, the clinical significance of kinase-impairing mutations remains unclear. The present study aimed to analyze kinase-impairing mutations in BRAF codons 594 and 596 in non-Caucasian patients with melanoma and to investigate their possible clinical significance. To detect hotspot mutations, exon 15 of the BRAF gene was amplified using polymerase chain reaction in samples from 1,554 patients with melanoma. Among these patients, a total of 912 valid follow-up data were obtained. These patients were divided into three groups according to their BRAF activation status: BRAF wild-type (n=752), BRAF V600E (n=147); and BRAF D594/G596 (n=13). Then the correlation between BRAF activation status, and the clinicopathological features and overall survival (OS) of the patients were analyzed. The prevalence of BRAF mutations in non-Caucasian patients with melanoma was 24.3% (377/1554). Three patients carried two mutations simultaneously. The overall mutation frequencies of kinase-activating mutations, kinase-impairing mutations, and mutations with unknown effects were 93.4 (355/380), 3.4 (13/380), and 3.2% (12/380), respectively. BRAF V600E was identified to be associated with a poor prognosis. Patients with BRAF mutations in codons 594 and 596 had a longer OS time compared with those with a BRAF V600E mutation [median OS, 45 vs. 25 months; HR, 0.45 (95% confidence interval, 0.31-0.97); P=0.043]. To the best of our knowledge, this is the first study to examine a large number of samples from non-Caucasian patients with melanoma and report the characteristics of BRAF mutations according to mutant kinase activity. Melanoma arising from a mutation in BRAF codon 594 or 596 can be differentiated from BRAF V600E-induced melanoma, and mutations in these codons may be good prognostic factors for melanoma. The results of the present study are thus of significance for the development of accurate personalized medicine to treat melanoma.

MAPK Pathway and TERT Promoter Gene Mutation Pattern and Its Prognostic Value in Melanoma Patients: A Retrospective Study of 2,793 Cases

Purpose: Ethnic differences are conspicuous in melanoma. This study is to obtain a comprehensive view of a genomic landscape and a better understanding of the correlations of gene mutation status with clinicopathologic characteristics and disease prognosis in the Asian population.Experimental Design: A total of 2,793 melanoma patient samples were retrospectively collected and analyzed for mutations in C-KIT, BRAF, NRAS, and PDGFRA coding regions and telomerase reverse transcriptase (TERT) promoter region by Sanger sequencing. Mutations were correlated to clinicopathologic features and overall survival.Results: The incidences of somatic mutations within the BRAF, NRAS, C-KIT, TERT-228, TERT-250, and PDGFRA genes were 23.7%, 10.4%, 8.0%, 5.9%, 5.5%, and 1.4%, respectively. Hotspot mutations accounted for 95.8% and 87.2% of BRAF and NRAS mutations, respectively; meanwhile, C-KIT and PDGFRA mutations showed more heterogeneity. BRAF, C-KIT, and NRAS mutations were mutually exclusive. BRAF, C-KIT, NRAS, and numbers of gene mutations of the MAPK pathway were all independent negative prognostic factors (P = 0.007, other P < 0.001, respectively). In acral melanoma, BRAF, C-KIT, and NRAS mutations were all independent prognostic factors of worse overall survival (all P < 0.001), whereas in mucosal melanoma, only C-KIT was (P = 0.006). Although correlated with BRAF mutations (P = 0.001 and P < 0.001 for C228T and C250T, respectively), TERT promoter gene mutations were not correlated with overall survival (P = 0.406 and 0.256, respectively).Conclusions: The MAPK pathway and TERT promoter gene mutations are differentially represented in the Asian population. Mutations in BRAF, C-KIT, and NRAS have prognostic values that vary by melanoma subtypes. Clinical treatment targeting these critical pathways should be aimed directly at these poor-prognosis subpopulations for maximum potential impact. Clin Cancer Res; 23(20); 6120-7. ©2017 AACR.

Frequency of BRAF V600E Mutation in the Mexican Population of Patients With Metastatic Melanoma

Purpose

The BRAF V600E mutation has been described in melanomas occurring in the Caucasian, European, and Asian populations. However, in the Mexican population, the status and clinical significance of BRAF mutation has not been researched on a large scale.

Methods

Consecutive BRAF-tested Mexican patients with metastatic melanoma (n = 127) were analyzed for mutations in exon 15 of the BRAF gene in genomic DNA by real-time polymerase chain reaction technology for amplification and detection. The results were correlated with the clinical-pathologic features and the prognosis of the patients.

Results

The frequency of somatic mutation V600E within the BRAF gene was 54.6% (43 of 127 patients). Nodular melanoma was the most prevalent subtype in our population, with BRAF mutations in 37.2% (16 of 55 patients). In contrast, superficial spread had a frequency of 18.6% BRAF mutation (eight of 24). Other clinicopathologic features were assessed to correlate with the mutation status.

Conclusion

This study searched for the most prevalent BRAF V600E mutation type in melanoma in a heterogeneous population from Mexico. Nodular melanoma was found to be the most prevalent in metastatic presentation and the presence of BRAF V600E mutation, perhaps related to the mixed ancestry; in the north, ancestry is predominantly European and in the south, it is predominantly Asian. The outcomes of the mutation correlations were similar to those found in other populations.

Racial Differences in Cancer Susceptibility and Survival: More Than the Color of the Skin?

Epidemiological studies point to race as a determining factor in cancer susceptibility. In US registries recording cancer incidence and survival by race (distinguishing 'black versus white'), individuals of African ancestry have a globally increased risk of malignancies compared with Caucasians and Asian Americans. Differences in socioeconomic status and health-care access play a key role. However, the lesser disease susceptibility of Hispanic populations with comparable lifestyles and socioeconomic status as African Americans (Hispanic paradox) points to the concomitant importance of genetic determinants. Here, we overview the molecular basis of racial disparity in cancer susceptibility ranging from genetic polymorphisms and cancer-driver gene mutations to obesity, chronic inflammation, and immune responses. We discuss implications for race-adapted cancer screening programs and clinical trials to reduce disparities in cancer burden.

Next-Generation Sequencing Reveals Pathway Activations and New Routes to Targeted Therapies in Cutaneous Metastatic Melanoma

BACKGROUND

Comprehensive genomic profiling of clinical samples by next-generation sequencing (NGS) can identify one or more therapy targets for the treatment of metastatic melanoma (MM) with a single diagnostic test.

METHODS

NGS was performed on hybridization-captured, adaptor ligation-based libraries using DNA extracted from 4 formalin-fixed paraffin-embedded sections cut at 10 microns from 30 MM cases. The exons of 182 cancer-related genes were fully sequenced using the Illumina HiSeq 2000 at an average sequencing depth of 1098X and evaluated for genomic alterations (GAs) including point mutations, insertions, deletions, copy number alterations, and select gene fusions/rearrangements. Clinically relevant GAs (CRGAs) were defined as those identifying commercially available targeted therapeutics or therapies in registered clinical trials.

RESULTS

The 30 American Joint Committee on Cancer Stage IV MM included 17 (57%) male and 13 (43%) female patients with a mean age of 59.5 years (range 41-83 years). All MM samples had at least 1 GA, and an average of 2.7 GA/sample (range 1-7) was identified. The mean number of GA did not differ based on age or sex; however, on average, significantly more GAs were identified in amelanotic and poorly differentiated MM. GAs were most commonly identified in BRAF (12 cases, 40%), CDKN2A (6 cases, 20%), NF1 (8 cases, 26.7%), and NRAS (6 cases, 20%). CRGAs were identified in all patients, and represented 77% of the GA (64/83) detected. The median and mean CRGAs per tumor were 2 and 2.1, respectively (range 1-7).

CONCLUSION

Comprehensive genomic profiling of MM, using a single diagnostic test, uncovers an unexpectedly high number of CRGA that would not be identified by standard of care testing. Moreover, NGS has the potential to influence therapy selection and can direct patients to enter relevant clinical trials evaluating promising targeted therapies.

Metastatic pathways in patients with cutaneous melanoma

Metastasis represents the end product of an elaborate biological process, which is determined by a complex interplay between metastatic tumour cells, host factors and homoeostatic mechanisms. Cutaneous melanoma can metastasize haematogenously or lymphogenously. The three predominant models that endeavour to explain the patterns of melanoma progression are the stepwise spread model, the simultaneous spread model and the model of differential spread. The time course to the development of metastases differs between the different metastatic routes. There are several clinical and histopathological risk factors for the different metastatic pathways. In particular, patient sex and the anatomical location of the primary tumour influence patterns of disease progression. There is limited existing evidence regarding the relationship between tumour mutation status, other diagnostic and prognostic biomarkers and the metastatic pathways of primary cutaneous melanoma. This knowledge gap needs to be addressed to better identify patients at high risk of disease recurrence and personalize surveillance strategies.

A comparison of immunohistochemical and molecular methods used for analyzing the BRAF V600E gene mutation in malignant melanoma in Taiwan

AIMS

The BRAF V600 mutation has been shown to be clinically meaningful in terms of both the prognosis and sensitivity of BRAF inhibitors in patients with metastatic melanoma. Recently, a BRAF V600E mutation-specific antibody, VE1, was generated for the detection of tumors bearing BRAF V600E mutations. To determine the clinical value of immunohistochemical testing, we compared the prevalence of mutant BRAF detected by VE1 with direct sequencing results.

METHODS

Paraffin-embedded, formalin-fixed melanoma biopsies were analyzed for the BRAF mutation status by immunohistochemistry with the VE1 antibody. Sanger sequencing was applied to verify the immunohistochemical results.

RESULTS

A total of 73 melanoma cases with tumor samples from primary lymph nodes and metastatic sites were selected for this study. Direct sequencing demonstrated that 18 of 73 cases (24.6%) harbored the BRAF V600 mutation: 17 with V600E and one with V600K. All 18 tumors shown to harbor the BRAF V600E/K mutations were VE1-positive. One additional case was false-positive for VE1. The sensitivity and specificity of VE1 was 100% (18/18) and 98% (54/55), respectively. The overall concordance between the immunohistochemical method and direct sequencing was excellent (98.6%).

CONCLUSIONS

Our findings demonstrate that immunohistochemical analysis using VE1 constitutes a highly sensitive test for the detection of BRAF mutations and suggest that this cost-effective method is suitable as a rapid diagnostic approach complementary to molecular testing.

BRAF and Epithelial-Mesenchymal Transition: Lessons From Papillary Thyroid Carcinoma and Primary Cutaneous Melanoma

The increased prevalence of BRAF mutations in thyroid carcinoma and primary cutaneous melanoma (PCM) hint that dysregulation of BRAF might contribute to the noted association between PCM and thyroid carcinoma. A recent study evaluating the rate of BRAFV600E mutations among patients who had been diagnosed with primary papillary thyroid carcinoma (PTC) and PCM showed that patients with either PCM or PTC were at an increased risk of developing the other as a second primary malignant neoplasm. Furthermore, the authors noted that samples from patients suffering from both malignancies exhibited a higher rate of incidence of the BRAFV600E mutation, compared with patients not suffering from both malignancies. These studies support the hypothesis that the pathogenesis of these 2 malignancies might share a conserved molecular pattern associated with dysregulation of the BRAF protein. One mechanism through which BRAF might contribute to PCM and thyroid carcinoma progression is through induction of epithelial-mesenchymal transition (EMT). Specifically, the Snail/E-cadherin axis has been demonstrated as a pathway dysregulated by BRAF, leading to EMT in both malignancies. Our analysis focuses on the results of these recent investigations, and through a review of select molecules relevant to EMT, looks to provide a context by which to better understand the relevance and role of stromal-parenchymal signaling and the BRAF mutation in the pathogenesis of PTC and PCM.

Malignant Melanoma of Vulva and Vagina: A Histomorphological Review and Mutation Analysis--A Single-Center Study

OBJECTIVES

The aim of this work was to determine molecular characteristics and specifically, the frequency of BRAF, C-KIT, and NRAS mutations in vulvar and vaginal melanomas.

METHODS

A retrospective review of all cases of vulvar and vaginal melanoma between 2002 and 2013 was performed. We reviewed the clinical and histological characteristics of all cases and performed genotyping studies on cases that had tissue available for the study, using next-generation sequencing.

RESULTS

We identified 33 vulvar and 11 vaginal melanomas in women with mean ages 58 and 61 years, respectively. Next-generation sequencing analysis on 20 cases (15 vulvar and 5 vaginal) identified a BRAF mutation in 7.6%, C-KIT mutation in 27.6%, NRAS mutation in 27.6%, and TP53 mutation in 7.6% of the vulvar cases. We detected only a single TP53 mutation in the vaginal cases. We did not identify any statistically significant relationship between the mutation status and patients' outcome, depth of invasion, ulceration, stage at presentation, or lymph node metastasis.

CONCLUSIONS

BRAF mutations are infrequent, whereas C-KIT and NRAS mutations are seen with higher frequency in vulvar melanomas than melanomas of other sites. These mutations can be considered as potential therapeutic targets in patients harboring them. Further studies are necessary to increase our understanding of mutational events occurring in melanoma of the lower female genital tract and their relationship with clinical parameters/outcome.

Dabrafenib: a new opportunity for the treatment of BRAF V600-positive melanoma

Prior to 2011, the 1-year survival rates for patients suffering from advanced or metastatic melanoma was as low as 33%, with a median overall survival of about 9 months. Several chemotherapeutic regimens have been applied, either as monochemotherapy or as polychemotherapy, overall not resulting in an improvement of progression-free or overall survival. Novel insights into the epidemiology and biology of melanoma allowed the development of newer therapies. The discovery of mutations in BRAF, a part of the mitogen-activated protein kinase, allowed the development of two BRAF inhibitors, vemurafenib and dabrafenib, which significantly improved the outcome of metastatic melanoma treatment. This article reviews the mechanism of action, efficacy, and safety profile of dabrafenib. An in-depth knowledge of this medication will encourage clinicians to select the appropriate therapeutic strategy for each patient, as well as to prevent or adequately manage side effects, optimizing, thus, the drug's applicability.

Molecular profiling, including TERT promoter mutations, of acral lentiginous melanomas

Acral lentiginous melanoma (ALM) is the less common subtype with singular characterization. TERT (human telomerase reverse transcriptase) promoter mutations have being described as recurrent in melanomas and infrequent in ALM, but their real incidence and clinical relevance is unclear. The objectives of this study were to describe the prevalence of TERT promoter mutations in ALM, and correlate with the molecular profile of other drive genes and clinical features. Sixty-one samples from 48 patients with ALM were analyzed. After DNA isolation, the mutation profiles of the hotspot region of BRAF, NRAS, KIT, PDGFRA, and TERT genes were determined by PCR amplification followed by direct Sanger sequencing. KIT, PDGFRA, and VEGFR2 gene amplification was performed by quantitative PCR. Clinical information such as survival, clinical stage, and Breslow tumor classification were obtained from medical records. TERT promoter mutations were found in 9.3% of the cases, BRAF in 10.3%, NRAS in 7.5%, KIT in 20.7%, and PDGFRA in 14.8% of ALM. None of the cases showed KIT, PDGFRA, or VEGFR2 gene amplification. We found an association between KIT mutations and advanced Clark level (IV and V, P=0.043) and TERT promoter mutations with low mitotic index. No other significant associations were observed between mutation profile and patients' clinical features nor survival rates. Oncogenic TERT promoter mutations are present in a fraction of ALMs. No relevant associations were found between TERT mutation status and clinical/molecular features nor survival. Mutations of KIT and PDGFRA are the most common genetic alterations, and they can be therapeutic targets for these patients.

BRAF-V600E expression in primary nodular melanoma is associated with aggressive tumour features and reduced survival

BACKGROUND

Around 50% of primary melanomas harbour BRAF mutations, but their prognostic impact has not been clear. Recently, a BRAF-V600E mutation-specific antibody has become available for immunohistochemistry. Here, we investigated for the first time the prognostic impact of BRAF-V600E protein expression in primary melanoma.

METHODS

In a patient series of 248 nodular melanomas, BRAF-V600E and total BRAF expression were assessed by immunohistochemistry using tissue microarray sections of paraffin-embedded archival tissue. Mutation status was assessed by real-time PCR in cases with sufficient tumour tissue (n=191).

RESULTS

Positive BRAF-V600E expression was present in 86 (35%) of the cases, and was significantly associated with increased tumour thickness, presence of tumour ulceration and reduced survival. Further, BRAF-V600E expression was an independent prognostic factor by multivariate analysis, whereas BRAF mutation status was not significant. There was 88% concordance between BRAF-V600E expression and mutation status.

CONCLUSIONS

Our findings indicate that BRAF-V600E expression is a novel prognostic marker in primary melanoma.

Promoter Methylation of PTEN Is a Significant Prognostic Factor in Melanoma Survival

Structural compromise of the tumor suppressor gene, phosphatase and tensin homolog (PTEN), occurs in 10% of melanoma specimens, and loss of PTEN expression through DNA methylation of the PTEN promoter region has also been reported in a number of other malignancies. However, the role of PTEN promoter methylation in melanoma is not well understood. We thus sought to elucidate the prevalence of PTEN promoter methylation in melanoma specimens, its relationship to clinical features, and its impact on the outcome of patients with melanoma. PTEN promoter methylation data were acquired from an archived primary Korean melanoma cohort (KMC) of 158 patients and, for validation, 234 patients from The Cancer Genome Atlas melanoma (TCGA-MEL) cohort. Hierarchical clustering was performed to identify PTEN "high methylated" and "low methylated" samples. Subsequently, differences in clinical features and outcomes based on PTEN promoter methylation status were then analyzed using SPSS and R. In the KMC, all tumors were acquired from primary tumors and 65.7% (n = 105) were acral or mucosal by site, whereas in the TCGA-MEL cohort, 90.5% of the tumors were from regional lymph node and distant metastatic lesions. Overall, 17.7% and 45.7% of the specimens harbored BRAF mutations in the KMC and TCGA-MEL cohort, respectively. Neuroblastoma RAS viral oncogene homolog was mutated in 12.2% and 26.9% of the tumors in the KMC and TCGA-MEL cohort, respectively. In the KMC, 31 cases (19.6%) were included in the high methylated group versus 142 cases (60.7%) in the TCGA-MEL cohort (P < 0.001). Multivariate Cox-regression analysis revealed promoter methylation of PTEN to be an independent negative prognostic factor for survival in both the KMC (hazard ratio 3.76, 95% confidence interval = 1.24-11.12, P = 0.017) and TCGA-MEL cohort (HR 1.88, 95% confidence interval = 1.13-3.12, P = 0.015). Our results indicate that PTEN promoter methylation is an independent predictor for impaired survival in patients with melanoma.

Prevalence of BRAF and NRAS mutations in cutaneous melanoma patients in Taiwan

BACKGROUND/PURPOSE

BRAF and NRAS mutations have been described in melanomas among Caucasians and some Asian populations. However, few large-scale studies have investigated the status and clinical significance of BRAF and NRAS mutations in a Taiwanese population.

METHODS

Melanoma samples (n = 119) were analyzed for mutations in exons 11 and 15 of the BRAF gene, and in exons 1 and 2 of the NRAS gene. The samples were studied in genomic DNA, using polymerase chain reaction amplification and Sanger sequencing. Mutations of the BRAF and NRAS genes were then correlated with clinicopathological features and patients' prognosis.

RESULTS

The incidence of somatic mutations within the BRAF and NRAS genes was 14.3% (17/119 patients) and 10.1% (12/119 patients), respectively. Among the 17 patients with BRAF mutations, 15 (88.2%) had V600E mutations. BRAF mutation was frequently detected in younger patients (p = 0.0035), in thin melanomas (p = 0.0181), and in melanomas with less ulceration (p = 0.0089). NRAS mutation was more often seen in patients with lymph node metastasis (p = 0.0332). Both BRAF and NRAS mutations were not significantly correlated with overall survival and disease-free survival.

CONCLUSION

As BRAF and NRAS mutations are rare in Taiwan, BRAF- or NRAS-targeted therapies may be effective only for selected Taiwanese melanoma patients.

Roads to melanoma: Key pathways and emerging players in melanoma progression and oncogenic signaling

Melanoma has markedly increased worldwide during the past several decades in the Caucasian population and is responsible for 80% of skin cancer deaths. Considering that metastatic melanoma is almost completely resistant to most current therapies and is linked with a poor patient prognosis, it is crucial to further investigate potential molecular targets. Major cell-autonomous drivers in the pathogenesis of this disease include the classical MAPK (i.e., RAS-RAF-MEK-ERK), WNT, and PI3K signaling pathways. These pathways play a major role in defining the progression of melanoma, and some have been the subject of recent pharmacological strategies to treat this belligerent disease. This review describes the latest advances in the understanding of melanoma progression and the major molecular pathways involved. In addition, we discuss the roles of emerging molecular players that are involved in melanoma pathogenesis, including the functional role of the melanoma tumor antigen, p97/MFI2 (melanotransferrin).

A histopathological study of melanocytic and pigmented skin lesions in patients with albinism

BACKGROUND

Oculocutaneous albinism (OCA) is a group of genetic disorders characterized by diminished pigmentation of the skin, hair and eyes. Individuals with OCA are at increased risk to develop sun-induced skin malignancies. The incidence of malignant melanoma in OCA individuals is, however, very low. The aim of this study was to document pigmented and melanocytic skin lesions occurring in patients with OCA.

METHODS

A prospective study was performed. Sixteen patients with OCA presenting at the Oncology and Dermatology Departments at Universitas Academic Hospital Annex in Bloemfontein, South Africa, were included. Selected clinically pigmented and/or melanocytic lesions were biopsied and studied by light microscopy.

RESULTS

Twenty-four punch biopsies were taken. Ten dendritic freckles and 10 melanocytic nevi were confirmed histologically. The nevi, which occurred in eight patients, were found on sun-protected skin. All the freckles occurred on sun-exposed skin. Twelve patients had current or previous skin malignancies. No melanomas were present in the study population. Other skin lesions ranged from solar keratoses to squamous cell carcinomas.

CONCLUSION

The majority of pigmented lesions were dendritic freckles that occurred on sun-exposed skin. None of the patients had a current or previous diagnosis of malignant melanoma.

Analysis of mTOR Gene Aberrations in Melanoma Patients and Evaluation of Their Sensitivity to PI3K-AKT-mTOR Pathway Inhibitors

PURPOSE

mTOR is a validated target in cancer. It remains to be determined whether melanoma patients bearing mTOR mutation could be selected for treatment with PI3K-AKT-mTOR pathway inhibitors.

EXPERIMENTAL DESIGN

A total of 412 melanoma samples were included. Gene aberrations in all exons of mTOR were detected by Sanger sequencing and confirmed by using Agilent's SureSelect Target Enrichment System. HEK293T cells stably expressing mTOR mutants were constructed by using transcription activator-like effector nucleases technique. Function of mTOR mutants and in vitro sensitivity of gain-of-function mTOR mutations to PI3K-AKT-mTOR pathway inhibitors were analyzed.

RESULTS

The overall incidence of somatic nonsynonymous mutations of mTOR was 10.4% (43/412). mTOR nonsynonymous mutations were relatively more frequent in acral (11.0%) and mucosal (14.3%) melanomas than in chronic sun-induced damage (CSD; 6.7%) and non-CSD (3.4%) melanomas. Of the 43 cases with mTOR mutations, 41 different mutations were detected, affecting 25 different exons. The median survival time for melanoma patients with mTOR nonsynonymous mutation was significantly shorter than that for patients without mTOR nonsynonymous mutation (P = 0.028). Transient expression of mTOR mutants in HEK293T cells strongly activated the mTOR-p70S6K pathway. In HEK293T cells with stable expression of H1968Y or P2213S mTOR mutants, LY294002 and AZD5363 showed higher potency than temsirolimus or BYL719 in inhibiting the PI3K-AKT-mTOR pathway and cell proliferation.

CONCLUSIONS

mTOR nonsynonymous mutations are frequent in melanoma patients. mTOR nonsynonymous mutation may predict a worse prognosis of melanoma. Clinical trials with PI3K-AKT-mTOR pathway inhibitors may be beneficial for melanoma patients with specific mTOR mutations.

BRAF V600 mutations and pathological features in Japanese melanoma patients

Ultraviolet radiation is a risk factor for BRAF V600 mutations frequently found in melanomas that cause constitutive BRAF activation. Primary sites of melanoma and the frequency of BRAF mutations might differ between races. Melanoma is rare in Japan (1500–2000 cases/year compared with 132 000/year worldwide) and the frequency and distribution of BRAF V600 mutations are unknown. We aimed to investigate the frequency of BRAF V600 mutations in a cohort of Japanese patients with melanoma and determine the relationship between mutations and clinical/pathologic features. DNA was extracted from 80 formalin-fixed, paraffin-embedded tumours from individuals diagnosed with melanoma. BRAF V600 mutations were detected using the Cobas 4800 System with z480 Analyzer and Cobas 4800 BRAF V600 Mutation Test reagents. BRAF V600 mutations were detected in 41.8% of tested tumours, with an invalid rate of 1.3%. The mutation rate was more than 60% in patients aged less than 60 years and more than 36% in patients with stage III/IV disease. No sex difference in the mutation rate was observed. BRAF V600 mutations were detected in 18.8% of acral lentiginous melanomas (ALMs), 64.7% of superficial spreading melanomas, 50.0% of lentigo maligna melanomas and 20.0% of nodular melanomas. Although the mutation rate was low in ALMs, 36.4% were mutation positive at stage III/IV compared with 9.5% at stage I/II. This study confirmed associations among BRAF V600 mutations, pathological features and subtypes of melanoma. BRAF V600 mutations were more frequent in late-stage ALMs than in early-stage ALMs. Superficial spreading melanomas had similar mutation rates at all stages. These insights suggest improved treatment predictions for stage III/IV melanoma patients.

Russian study of morphological prognostic factors characterization in BRAF-mutant cutaneous melanoma

Melanoma is one of the aggressive cancer types causing the majority of deaths in skin cancer patients. Mutational screening of the tumor revealed a number of driver mutations in oncogenes which enabled melanoma classification into a few molecular subtypes. BRAF is a key component of mitogen-activated kinase pathway; its activating mutation leads to accelerated melanoma cells proliferation, invasion and survival. Somatic mutations in BRAF were reported in various malignancies, including thyroid cancer, colorectal cancer and melanoma. Specific features of BRAF-positive tumors could have clinical implications as mutational alterations may have an impact on the biological behavior of the tumor and prognosis of the disease. In the present study, the frequency of BRAF V600E mutation was evaluated in Russian patients with melanocytic lesions, of which 41.25% were primary melanoma and 60% were melanocytic nevi. Melanoma patients with trunk localization were of younger age in the BRAF-positive group as compared with BRAF-negative patients. Immunohistochemical evaluations of Ki-67 expression, as well as matrix metalloproteinase-2, -9, were found to be equal in BRAF-positive and BRAF-negative tumors. MMP-2/MMP-9 immunoreactivity was observed in stromal and/or melanocytic cells both in melanoma and nevi patients. Besides tumor cells, MMP-9 expression was observed in lymphocytes in 27.2% of BRAF-positive and in 19.1% of BRAF-negative patients. Histopathological prognostic markers (Breslow thickness, mitotic index, ulceration, tumor infiltrating lymphocytes pattern) did not show any differences depending on BRAF V600E mutational status. The frequency of BRAF-positive melanomas in Russian cohort is similar to other Caucasian population rates. BRAF V600E mutation harboring tumors are more often observed in younger patients without specific features of morphological prognostic factors.

The role of BRAF mutations in primary melanoma growth rate and survival

BACKGROUND

The clinical behaviour and prognosis of primary melanomas harbouring BRAF mutations is not fully understood.

OBJECTIVES

To investigate the effect of mutation status on primary melanoma growth rate and melanoma-specific survival (MSS).

METHODS

A prospective cohort of 196 patients with stage I-III primary cutaneous melanoma were followed for a median of 92 months, pre-dating the institution of BRAF inhibitor therapy. Clinicopathological variables were correlated with mutation status and hazard ratios (HRs) estimated for MSS.

RESULTS

Of 196 tumours, 77 (39.2%) were BRAF V600E, 10 (5.1%) BRAF V600K and 33 (16.8%) were NRAS mutant. BRAF V600E mutant melanomas were associated with favourable clinical characteristics and tended to be slower growing compared with BRAF V600K, NRAS mutant or BRAF/NRAS wild-type tumours (0.12 mm per month, 0.61 mm per month, 0.36 mm per month and 0.23 mm per month, respectively; P = 0.05). There were 39 melanoma deaths, and BRAF mutant melanomas were associated with poorer MSS in stage I-III disease [HR 2.60, 95% confidence interval (CI) 1.20-5.63; P = 0.02] and stage I-II disease (HR 3.39, 95% CI 1.12-10.22; P = 0.03) after adjusting for other prognostic variables. Considered separately, BRAF V600E mutant melanomas were strongly associated with MSS independently of thickness and nodal status (HR 3.89, 95% CI 1.67-9.09; P < 0.01) but BRAF V600K mutant tumours were not (HR 1.19, 95% CI 0.36-3.92; P = 0.77).

CONCLUSIONS

The presence of a BRAF mutation does not necessarily 'drive' more rapid tumour growth but is associated with poorer MSS in patients with early-stage disease.

Metaanalysis of BRAF mutations and clinicopathologic characteristics in primary melanoma

BACKGROUND

BRAF mutations occur in some melanomas. We hypothesized that BRAF mutation rates may differ in melanomas found in Asian compared to white populations.

OBJECTIVE

We performed a metaanalysis of BRAF mutations and their associations with the clinicopathologic characteristics of primary melanoma (PM), with a subgroup analysis to compare Asian and white patients with PM.

METHODS

The PubMed, EMBASE, and Cochrane databases were searched up to November 2013. The incidence rates and odds ratios (ORs) of BRAF mutations were calculated using a fixed or random effects model.

RESULTS

BRAF mutation was associated with younger age (OR = 1.734; P < .001), trunk location (OR = 2.272; P < .001), non-chronically sun damaged skin (OR = 2.833; P < .001), superficial spreading melanoma (OR = 2.081; P < .001), and advanced melanoma stage (OR = 1.551; P = .003). The incidence of BRAF mutations in Asian patients with PM was half that of white patients with PM, but it was linked to the same clinicopathologic characteristics.

LIMITATIONS

Only a small number of studies have been conducted on Asian patients with PMs.

CONCLUSIONS

The BRAF mutation in PM was associated with age, anatomic site based on ultraviolet radiation exposure, histologic subtype, and advanced stage of melanoma. The clinicopathologic associations with BRAF mutations were similar in Asian and white patients with PM.

Prognostic factors for Taiwanese patients with cutaneous melanoma undergoing sentinel lymph node biopsy

BACKGROUND/PURPOSE

Sentinel lymph node biopsy (SLNB) is a standard procedure in the management of clinically node-negative melanoma. However, few studies have been performed on SLNB in Asia, which is an acral melanoma-prevalent area. This study evaluated the clinicopathologic prognostic factors of disease-free survival (DFS) and overall survival (OS) in Taiwanese patients with cutaneous melanoma who received wide excision and SLNB. The prognosis of patients with false-negative (FN) SLNB was also evaluated.

METHODS

Malignant melanoma cases were reviewed for 518 patients who were treated between January 2000 and December 2011. Of these patients, 127 patients with node-negative cutaneous melanoma who received successful SLNB were eligible for inclusion in the study.

RESULTS

The SLNB-positive rate was 34.6%. The median DFS was 51.5 months, and the median OS was 90.9 months at the median follow-up of 36.6 months. Multivariate analysis revealed that patients whose melanoma had a Breslow thickness greater than 2 mm had a significantly shorter DFS than patients whose melanoma had a Breslow thickness of 2 mm or less [hazard ratio (HR), 3.421; p = 0.005]. Independent prognostic factors of OS were a Breslow thickness greater than 2 mm (HR, 4.435; p = 0.002); nonacral melanoma (HR, 3.048; p = 0.001); and an age older than 65 years (HR, 2.819; p = 0.036). During the follow-up period, 13 of 83 SLN-negative patients developed a regional nodal recurrence. The SLNB failure rate was 15.7% and the FN rate was 22.8%. Compared to patients with a true-positive SLNB, patients with FN SLNB had a significantly shorter DFS (p = 0.001) but no significant difference in OS (p = 0.262).

CONCLUSION

Except for the pathologic subtypes, prognostic factors in Taiwan are similar to those used in other melanoma-prevalent countries. Identifying and closely monitoring patients at risk of nodal recurrence after a negative SLNB is important.

Melanoma arising from a long-standing pigmented trichoblastoma: clinicopathologic study with complementary aCGH/mutational analysis

Trichoblastoma is a benign cutaneous adnexal tumor, composed mostly of follicular germinative cells. Its pigmented variant is colonized by numerous dendritic melanocytes. So far, only one case in the literature describes a combination of trichoblastoma and melanoma. We report the case of a 62-year-old man who had a slow-growing mass of the left flank present since childhood. This 8-cm mass was surgically removed when it became ulcerated and associated with axillary lymph nodes. Histologically, this tumor was strictly dermal and composed of 2 intermingled components. Large sheets of atypical, proliferating epithelioid cells predominated. Dispersed solid nests or cribriform epithelial islets encased in fibrous tissue were also seen. Some nests displayed a massive colonization by pigmented dendritic melanocytes. On immunohistochemical staining, the sheets of atypical cells expressed focally but strongly S100 protein, MelanA, HMB45, and MiTF. Epithelial structures diffusely expressed pancytokeratin AE1/AE3, KL1, and pleckstrin homology-like domain, family A, member 1. Based on these results, we diagnosed an intradermal melanoma, possibly developed from dendritic melanocytes colonizing a giant pigmented trichoblastoma. Direct sequencing of the melanoma revealed a rarely described NRAS mutation c.34G>T (G12C). Array comparative genomic hybridization displayed a complex profile somewhat divergent from standard melanoma profiles. The patient died of widespread metastatic disease 8 months after initial diagnosis.

IMP-3 promotes migration and invasion of melanoma cells by modulating the expression of HMGA2 and predicts poor prognosis in melanoma

IGF II mRNA-binding protein 3 (IMP-3) has been reported to be a marker of melanoma progression. However, the mechanisms by which it impacts melanoma are incompletely understood. In this study, we investigate the clinical significance of IMP-3 in melanoma progression and also its underlying mechanisms. We found that IMP-3 expression was much higher in advanced-stage/metastatic melanomas and that it was associated with a poor prognosis (P=0.001). Univariate analysis showed that IMP-3 expression was associated with stage III/IV melanomas (odds ratio=5.40, P=0.031) and the acral lentiginous subtype (odds ratio=3.93, P=0.0034). MeWo cells with overexpression of IMP-3 showed enhanced proliferation and migration and significantly increased tumorigenesis and metastatic ability in nude mice. We further demonstrated that IMP-3 could bind and enhance the stability of the mRNA of high mobility group AT-hook 2 (HMGA2). It was also confirmed that IMP-3 had an important role in melanoma invasion and metastasis through regulating HMGA2 mRNA expression. IMP-3 expression was positively correlated with HMGA2 expression in melanoma cells and also in melanoma tissues. Our results show that IMP-3 expression is a strong prognostic factor for melanoma, especially acral lentiginous melanoma.

Somatic DNA mutation analysis in targeted therapy of solid tumours

Cancer is a disease of the genome with diverse aetiologies including the accumulation of acquired mutations throughout the genome. There has been a flood of knowledge improving our understanding of the biology and molecular genetics of melanoma, lung and colorectal cancer since the genomics era started. Translation of this knowledge into a better understanding of cell proliferation, survival and apoptosis has produced a paradigm shift in medical oncology enabling gene-based cancer treatment (called personalised or precision medicine). Somatic mutation analysis is crucial for a genomics approach since it can identify driver mutations-the "Achilles' heel" of cancer, and support clinical decision-making through targeted therapy. Nevertheless, the applications of somatic DNA testing in cancer face many challenges such as obtaining comprehensive coverage of the cancer genome with limited DNA being available, and delivering an accurate report in a timely fashion without false-negative and false-positive results. Further advances in DNA technologies and bioinformatics will overcome these issues and maximise opportunities for targeted therapy. Somatic mutation analysis will then become an integral part of cancer management for all malignancies.

Immunohistochemistry is highly sensitive and specific for the detection of NRASQ61R mutation in melanoma

Testing for NRAS is now integral part in the assessment of metastatic melanoma patients because there is evidence that NRAS-mutated patients may be sensitive to MEK inhibitors, and RAS mutation is a common mechanism of acquired resistance during treatment with BRAF inhibitors. This study evaluated the sensitivity and specificity of immunohistochemical analysis using an N-Ras (Q61R) antibody to detect the presence of the NRASQ61R mutation in melanoma patients. A total of 98 primary cutaneous melanomas that have undergone examination of NRAS mutation were retrieved from a multicentric database. Formalin-fixed and paraffin-embedded melanoma tissues were analyzed for BRAF and NRAS mutations by independent, blinded observers using both conventional DNA molecular techniques and immunohistochemistry with the novel anti-human N-Ras (Q61R) monoclonal antibody (clone SP174). The antibody showed a sensitivity of 100% (14/14) and a specificity of 100% (83/83) for detecting the presence of an NRASQ61R mutation. Of the NRAS-mutated cases, none of the non-Q61R cases stained positive with the antibody (0/7). There were three cases with discordant NRAS mutational results. Additional molecular analysis confirmed the immunohistochemically obtained NRAS result in all cases, suggesting that a multiple analytical approach can be required to reach the correct sample classification. The reported immunohistochemical method is an accurate, rapid, and cost-effective method for detecting NRASQ61R mutation in melanoma patients, and represents a valuable supplement to traditional mutation testing. If validated in further studies, genetic testing would only be required for immunohistochemistry-negative patients to detect non-Q61R mutations.

PTEN Methylation Dependent Sinonasal Mucosal Melanoma

Sinonasal mucosal melanoma (SMM) is an aggressive and rare type of melanoma. Although the classic RAS-RAF-MEK pathway is thought to be the main pathway involved in melanoma pathogenesis, genetic alterations in the phosphatidylinositol 3-kinase-AKT pathway, including PTEN-regulated signaling, are also thought to contribute. So far, data regarding altered PTEN expression and epigenetic mechanism of PTEN silencing in development of SMM is extremely limited. Herein we report on a case of SMM with liver and bone metastases with an epigenetic alteration of PTEN. Results of mutation analysis for BRAF, NRAS, HRAS, KRAS, PIK3CA, c-Kit, and PTEN were negative; however, methylation of PTEN CpG islands was observed. Our case not only supports PTEN as a major tumor suppressor involved in melanoma tumorigenesis, but also a potential epigenetic mechanism of PTEN silencing in development of SMM.

Response to MAPK pathway inhibitors in BRAF V600M-mutated metastatic melanoma

WHAT IS KNOWN AND OBJECTIVE

The management of metastatic melanoma has changed significantly in the past decade with the development of immunotherapies and targeted molecular therapies. Trials of targeted therapies have focused mainly on patients with the most common BRAF V600 mutations, namely V600E/K substitutions, with very little information available on the benefit of targeted therapies on less commonly occurring mutations such as V600R/D and M.

CASE SUMMARY

We present a 54-year-old man with metastatic melanoma harbouring a rare BRAF V600M mutation, who experienced clinical and radiological response to combined therapy with the BRAF inhibitor dabrafenib and MEK inhibitor trametinib.

WHAT IS NEW AND CONCLUSION

As our understanding of these therapies evolves and an increasing number of patients have mutational testing performed, there is a clear imperative--as highlighted by this case--to test for rarer mutations and facilitate their inclusion both in everyday practice and in future clinical trials.

Immunohistochemical detection of the BRAF V600E mutation in melanoma patients with monoclonal antibody VE1

A novel mutation-specific monoclonal antibody VE1 was generated to detect BRAF V600E mutation with immunohistochemistry. This study aims to investigate the sensitivity and specificity of immunohistochemistry compared with conventional Sanger sequencing and to evaluate whether IHC would become the routine screening method of BRAF V600E mutation. A total of 84 cases of melanoma lesion specimens were selected to make the tissue microarray and to perform IHC with VE1 antibody. Simultaneously Sanger sequencing was applied to test and verify. VE1 has a high specificity (100%) and sensitivity (72.2%), and the concordance between the two techniques is excellent (93.8% cases coherent and kappa = 0.801). As a rapid, cost-effective method, IHC may become the routine diagnostic means for the detection of BRAF V600E mutation of malignant melanomas in the near future, and the recommended detection process is initial immunohistochemical staining for positive cases, followed by molecular techniques for negative or ambiguous cases.

BRAF gene: From human cancers to developmental syndromes

The BRAF gene encodes for a serine/threonine protein kinase that participates in the MAPK/ERK signalling pathway and plays a vital role in cancers and developmental syndromes (RASopathies). The current review discusses the clinical significance of the BRAF gene and other members of RAS/RAF cascade in human cancers and RAS/MAPK syndromes, and focuses the molecular basis and clinical genetics of BRAF to better understand its parallel involvement in both tumourigenesis and RAS/MAPK syndromes—Noonan syndrome, cardio-facio-cutaneous syndrome and LEOPARD syndrome.

Oncogenic GNAQ and GNA11 mutations in uveal melanoma in Chinese

Purpose

To examine whether GNAQ and GNA11 somatic mutations previously identified in uveal melanomas of Caucasians are associated with uveal melanomas in Chinese patients.

Methods

Uveal melanomas treated by primary enucleation in Chinese patients underwent a mutation analysis of GNAQ and GNA11 with sequencing of exon 5 and exon 4.

Results

The study included 50 patients with uveal melanoma and with a mean age of 47.6±13.0 years. During the follow-up of at least 3 years, 20 (40%) patients developed extraocular metastases. The frequencies of GNAQ and GNA11 somatic mutations in uveal melanoma were 18% (9/50) and 20% (10/50), respectively. The mutations occurred exclusively in codon 209 of exon 5. No mutations were detected in exon 4. Mutations affecting codon 209 in GNAQ were c.626A>C(Q209P) (78%) and c.626A>T(Q209L) (22%). Mutations affecting codon 209 in GNA11 were exclusively c.626A>T(Q209L) (100%). In none of the tumors, mutations of BRAF and NRAS were detected. GNAQ/11 mutations were marginally (P = 0.045) associated with optic disc involvement. In Kaplan-Meier analysis, metastasis-free survival was not significantly (P = 0.94) associated with GNAQ/11 mutations.

Conclusions

Mutations of GNAQ and GNA11 can be found in Chinese patients as in Caucasian patients with uveal melanoma, with a higher frequency reported for Caucasian patients.

The ginsenoside 20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol induces autophagy and apoptosis in human melanoma via AMPK/JNK phosphorylation

Studies have shown that a major metabolite of the red ginseng ginsenoside Rb1, called 20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol (GPD), exhibits anticancer properties. However, the chemotherapeutic effects and molecular mechanisms behind GPD action in human melanoma have not been previously investigated. Here we report the anticancer activity of GPD and its mechanism of action in melanoma cells. GPD, but not its parent compound Rb1, inhibited melanoma cell proliferation in a dose-dependent manner. Further investigation revealed that GPD treatment achieved this inhibition through the induction of autophagy and apoptosis, while Rb1 failed to show significant effect at the same concentrations. The inhibitory effect of GPD appears to be mediated through the induction of AMPK and the subsequent attenuation of mTOR phosphorylation. In addition, GPD activated c-Jun by inducing JNK phosphorylation. Our findings suggest that GPD suppresses melanoma growth by inducing autophagic cell death and apoptosis via AMPK/JNK pathway activation. GPD therefore has the potential to be developed as a chemotherapeutic agent for the treatment of human melanoma.

Genomic medicine for cancer prognosis

There is a heavy research emphasis on prognostic and predictive approaches based on genomic data, which has in turn challenged standard paradigms for the management of patients with malignant disease. This review will highlight the recent advances made in genomic medicine, specifically with regard to prognosis associated with thyroid cancer, cutaneous melanoma, and pancreatic adenocarcinoma. Although none of the markers reviewed have been incorporated into routine clinical practice, this review covers the most promising ones.

Nras in melanoma: targeting the undruggable target

RAS belongs to the guanosine 5'-triphosphate (GTP)-binding proteins' family, and oncogenic mutations in codons 12, 13, or 61 of RAS family occur in approximately one third of all human cancers with N-RAS mutations found in about 15-20% of melanomas. The importance of RAS signaling as a potential target in cancer is emphasized not only by the prevalence of RAS mutations, but also by the high number of RAS activators and effectors identified in mammalian cells that places the RAS proteins at the crossroads of several, important signaling networks. Ras proteins are crucial crossroads of signaling pathways that link the activation of cell surface receptors with a wide variety of cellular processes leading to the control of proliferation, apoptosis and differentiation. Furthermore, oncogenic ras proteins interfere with metabolism of tumor cells, microenvironment's remodeling, evasion of the immune response, and finally contributes to the metastatic process. After 40 years of basic, translational and clinical research, much is now known about the molecular mechanisms by which these monomeric guanosine triphosphatase-binding proteins promote cellular malignancy, and it is clear that they regulate signaling pathways involved in the control of cell proliferation, survival, and invasiveness. In this review we summarize the biological role of RAS in cancer by focusing our attention on the biological rational and strategies to target RAS in melanoma.