Analysis of variants induced by combined ex vivo irradiation and in vivo tumorigenesis suggests a role for the ZNF831 p.R1393Q mutation in cutaneous melanoma development.

Ultraviolet (UV) radiation is known to be the most important environmental carcinogen for cutaneous melanoma. While genomic analyses of melanoma tumors implicate a high rate of UV damage, the experimental induction and recovery of bona fide UV-signature changes have not been directly observed. To replicate recurrent UV mutations from TCGA_SKCM specimens, we UV-irradiated cultured immortalized human melanocytes and subjected them to in vivo tumorigenesis assays.

Molecular Analysis of Murine Kit Melanoma Progression.

Acral and mucosal melanomas are often driven by sequence variants in the KIT receptor tyrosine kinase, with nearly 40% harboring alterations in the locus. Despite advances in the knowledge of -mutated melanomas, little is known about the molecular reprogramming that occurs during KIT-mediated melanoma progression owing to the rarity of acral and mucosal melanomas and the lack of comprehensive biological tools and models. To this end, we used a murine model that allows us to ascertain the molecular underpinnings of the stages of cancer progression-transformation, tumorigenesis, immune engagement, and tumor escalation.

DNA promoter hypermethylation of melanocyte lineage genes determines melanoma phenotype.

Cellular stress contributes to the capacity of melanoma cells to undergo phenotype switching into highly migratory and drug-tolerant dedifferentiated states. Such dedifferentiated melanoma cell states are marked by loss of melanocyte-specific gene expression and increase of mesenchymal markers. Two crucial transcription factors, microphthalmia-associated transcription factor (MITF) and SRY-box transcription factor 10 (SOX10), important in melanoma development and progression, have been implicated in this process.

Oncogenic KIT Induces Replication Stress and Confers Cell Cycle Checkpoint Vulnerability in Melanoma.

Acral and mucosal melanomas arise from sun-protected sites, disproportionately impact darker-skinned individuals, and exact higher mortality than common types of cutaneous melanoma. Genetically, acral and mucosal melanomas harbor more alterations of KIT than typical cutaneous melanomas. Because KIT-mutated melanomas remain largely treatment resistant, we set out to create a faithful murine KIT-driven allograft model to define newer therapeutic strategies.

Loss of ACK1 Upregulates EGFR and Mediates Resistance to BRAF Inhibition.

Targeted BRAF(V600E) suppression by selective BRAF inhibitors (BRAFis; e.g., vemurafenib and dabrafenib) has led to a sea change in the treatment of metastatic melanoma.

Cancer risks associated with the germline MITF(E318K) variant.

The MITF(E318K) variant confers moderate risk for cutaneous melanoma. While there are small studies suggesting that this risk is associated with other malignancies (e.g.

Hypoxia and HIF-1α Regulate Collagen Production in Keloids.

Keloids are reactive or spontaneous fibroproliferative dermal tumors characterized by the exaggerated and uncontrolled accumulation of extracellular collagen. Current approaches to mitigate keloidogenesis are largely procedural in nature. However, a better understanding of its biological drivers may lead to novel targeted treatments for keloids.

Classifying Melanoma by TERT Promoter Mutational Status.

Although TERT promoter mutations have been associated with a worsened prognosis in melanoma, the relationship between mutation status and downstream telomerase activity and telomere length remains convoluted. Using Sanger sequencing and techniques based on quantitative reverse transcriptase in real time, we evaluated 60 melanoma cell lines for TERT promoter mutational status, copy number, gene expression, and telomere length to provide a comprehensive analysis of the TERT/telomere pathway and establish a classification system whereby the associations between TERT mutations and their downstream molecular manifestations can more easily be ascertained. Mutations at positions -124/125 and -146 were associated with the highest levels of TERT gene expression but had no appreciable impact on absolute telomere length.

Growth suppression by dual BRAF(V600E) and NRAS(Q61) oncogene expression is mediated by SPRY4 in melanoma.

The underlying forces that shape mutational patterns within any type of cancer have been poorly characterized. One of the best preserved exclusionary relationships is that between BRAF(V600E) and NRAS(Q61) in melanomas. To explore possible mechanisms which could explain this phenomenon, we overexpressed NRAS(Q61) in a set of BRAF(V600E) melanoma lines and vice versa.

Use of Targeted Next-Generation Sequencing to Identify Activating Hot Spot Mutations in Cherry Angiomas.

Importance: Shared gene variants in benign-malignant process pairs, such as BRAF mutations common to benign nevi and melanoma, are associated with differing phenotypic manifestations. Study of gene mechanisms underlying cherry angioma may uncover previously unknown disease relationships.

Objective: To identify somatic mutations present in cherry angioma specimens by using targeted next-generation sequencing.

Comprehensive Study of the Clinical Phenotype of Germline BAP1 Variant-Carrying Families Worldwide.

Background: The BRCA1-associated protein-1 (BAP1) tumor predisposition syndrome (BAP1-TPDS) is a hereditary tumor syndrome caused by germline pathogenic variants in BAP1 encoding a tumor suppressor associated with uveal melanoma, mesothelioma, cutaneous melanoma, renal cell carcinoma, and cutaneous BAP1-inactivated melanocytic tumors. However, the full spectrum of tumors associated with the syndrome is yet to be determined. Improved understanding of the BAP1-TPDS is crucial for appropriate clinical management of BAP1 germline variant carriers and their families, including genetic counseling and surveillance for new tumors.

Rare Variant, Gene-Based Association Study of Hereditary Melanoma Using Whole-Exome Sequencing.

Background: Extraordinary progress has been made in our understanding of common variants in many diseases, including melanoma. Because the contribution of rare coding variants is not as well characterized, we performed an exome-wide, gene-based association study of familial cutaneous melanoma (CM) and ocular melanoma (OM).

Methods: Using 11 990 jointly processed individual DNA samples, whole-exome sequencing was performed, followed by large-scale joint variant calling using GATK (Genome Analysis ToolKit).

High MITF Expression Is Associated with Super-Enhancers and Suppressed by CDK7 Inhibition in Melanoma.

Cutaneous melanoma is an aggressive tumor that accounts for most skin cancer deaths. Among the physiological barriers against therapeutic success is a strong survival program driven by genes such as MITF that specify melanocyte identity, a phenomenon known in melanoma biology as lineage dependency. MITF overexpression is occasionally explained by gene amplification, but here we show that super-enhancers are also important determinants of MITF overexpression in some melanoma cell lines and tumors.

Genotypic and Phenotypic Features of BAP1 Cancer Syndrome: A Report of 8 New Families and Review of Cases in the Literature.

Importance: Patients with germline mutations in BAP1 may develop several flesh-colored melanocytic BAP1-mutated atypical intradermal tumors (MBAITs). These tumors generally develop earlier than other BAP1-associated tumors, highlighting an important role for dermatologists in identifying and screening patients with a history suggestive of a germline mutation.

Objective: To describe 8 new families with germline mutations in BAP1 and provide a comprehensive review of reported cases.

Multiple Cutaneous Melanomas and Clinically Atypical Moles in a Patient With a Novel Germline BAP1 Mutation.

Importance: Several kindreds having germline BAP1 mutations with a propensity for uveal and cutaneous melanomas and other internal malignancies have been described in an autosomal dominant tumor predisposition syndrome. However, clinically atypical moles have not been previously recognized as a component of this syndrome, to our knowledge. We describe the first kindred to date with a germline mutation in BAP1 associated with multiple cutaneous melanomas and classic dysplastic nevus syndrome.

Aggressive skull base metastasis from uveal melanoma: a clinicopathologic study.

Purpose: We present the clinical, pathologic, and genetic findings of the first reported case of choroidal melanoma that developed a late recurrence and aggressive metastasis to the skull base without evidence of hepatic involvement.

Methods: Retrospective chart review and clinicopathologic correlation of ocular and brain tissue, including sequencing of BAP1 for mutations.

Results: A 55-year-old woman was diagnosed with choroidal melanoma and treated with proton radiotherapy.

Vemurafenib synergizes with nutlin-3 to deplete survivin and suppresses melanoma viability and tumor growth.

Purpose: For patients with advanced melanoma, primary and secondary resistance to selective BRAF inhibition remains one of the most critically compelling challenges. One rationale argues that novel biologically informed strategies are needed to maximally cripple melanoma cells up front before compensatory mechanisms emerge. As p53 is uncommonly mutated in melanoma, restoration of its function represents an attractive adjunct to selective BRAF inhibition.

Germline BAP1 inactivation is preferentially associated with metastatic ocular melanoma and cutaneous-ocular melanoma families.

Background: BAP1 has been shown to be a target of both somatic alteration in high-risk ocular melanomas (OM) and germline inactivation in a few individuals from cancer-prone families. These findings suggest that constitutional BAP1 changes may predispose individuals to metastatic OM and that familial permeation of deleterious alleles could delineate a new cancer syndrome.

Design: To characterize BAP1's contribution to melanoma risk, we sequenced BAP1 in a set of 100 patients with OM, including 50 metastatic OM cases and 50 matched non-metastatic OM controls, and 200 individuals with cutaneous melanoma (CM) including 7 CM patients from CM-OM families and 193 CM patients from CM-non-OM kindreds.

p53 rescue through HDM2 antagonism suppresses melanoma growth and potentiates MEK inhibition.

Oncogenesis reflects an orchestrated interaction between misguided growth signals. Although much effort has been launched to pharmacologically disable activated oncogenes, one sidelined approach is the restoration of tumor suppressive signals. As TP53 is often structurally preserved, but functionally crippled, by CDKN2A/ARF loss in melanoma, rescue of p53 function represents an attractive point of vulnerability in melanoma.

Selective BRAFV600E inhibition enhances T-cell recognition of melanoma without affecting lymphocyte function.

Targeted therapy against the BRAF/mitogen-activated protein kinase (MAPK) pathway is a promising new therapeutic approach for the treatment of melanoma. Treatment with selective BRAF inhibitors results in a high initial response rate but limited duration of response. To counter this, investigators propose combining this therapy with other targeted agents, addressing the issue of redundancy and signaling through different oncogenic pathways.

Dynamic gene expression analysis links melanocyte growth arrest with nevogenesis.

Like all primary cells in vitro, normal human melanocytes exhibit a physiologic decay in proliferative potential as it transitions to a growth-arrested state. The underlying transcriptional program(s) that regulate this phenotypic change is largely unknown. To identify molecular determinants of this process, we performed a Bayesian-based dynamic gene expression analysis on primary melanocytes undergoing proliferative arrest.

EphA2 is an essential mediator of UV radiation-induced apoptosis.

One of the physiologic consequences of excessive UV radiation (UVR) exposure is apoptosis. This critical response serves to eliminate genetically injured cells and arises, in part, from activation of DNA damage and p53 signaling. Other contributory pathways, however, likely exist but have not been fully characterized.

A one-plasmid conditional color-switching transgenic system for multimodal bioimaging.

We have developed a new construct to generate transgenic mice with one plasmid that offers: (1) Cre/loxP-mediated spatial and temporally-controlled tissue-specific transgene expression; (2) A color-switching mechanism that uses spectrum-complementary genetically-encoded red (mRFP) and green (eGFP) fluorescent markers to label the transgene-expressing cells; (3) A bioluminescent marker that turns-on in the transgene-expressing cells; (4) eGFP as a cell surface marker in the transgene-expressing cells that facilitates the isolation and targeting of these cells. This vector was tested in vitro by co-transfection of the transgenic plasmid and a plasmid containing Cre recombinase into cultured cells and by establishing a transgenic mouse line. We show that this method allows versatile transgene expression targeting and color-switching to facilitate fluorescent and bioluminescent imaging both in cultured cells and in vivo.