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Metastasis and failure of present-day therapies represent the most common causes of mortality in patients with cutaneous melanoma. To identify the underlying genetic and transcriptomic landscapes, in this study we analyzed multi-organ metastases and tumor-adjacent tissues from 11 rapid autopsies after treatment with MAPK inhibitor (MAPKi) and/or immune checkpoint blockade (ICB) and death due to acquired resistance. Either treatment elicits shared genetic alterations that suggest immune-evasive, cross-therapy resistance mechanisms. Large, non-clustered deletions, inversions and inter-chromosomal translocations dominate rearrangements. Analyzing data from separate melanoma cohorts including 345 therapy-naive patients and 35 patients with patient-matched pre-treatment and post-acquired resistance tumor samples, we performed cross-cohort analyses to identify MAPKi and ICB as respective contributors to gene amplifications and deletions enriched in autopsy versus therapy-naive tumors. In the autopsy cohort, private/late mutations and structural variants display shifted mutational and rearrangement signatures, with MAPKi specifically selecting for signatures of defective homologous-recombination, mismatch and base-excision repair. Transcriptomic signatures and crosstalks with tumor-adjacent macroenvironments nominated organ-specific adaptive pathways. An immune-desert, CD8 + -macrophage-biased archetype, T-cell exhaustion and type-2 immunity characterized the immune contexture. This multi-organ analysis of therapy-resistant melanoma presents preliminary insights with potential to improve therapeutic strategies., (© 2023. The Author(s).)

Blocking cancer genomic instability may prevent tumor diversification and escape from therapies. We show that, after MAPK inhibitor (MAPKi) therapy in patients and mice bearing patient-derived xenografts (PDX), acquired resistant genomes of metastatic cutaneous melanoma specifically amplify resistance-driver, nonhomologous end-joining (NHEJ), and homologous recombination repair (HRR) genes via complex genomic rearrangements (CGR) and extrachromosomal DNAs (ecDNA). Almost all sensitive and acquired-resistant genomes harbor pervasive chromothriptic regions with disproportionately high mutational burdens and significant overlaps with ecDNA and CGR spans. Recurrently, somatic mutations within ecDNA and CGR amplicons enrich for HRR signatures, particularly within acquired resistant tumors. Regardless of sensitivity or resistance, breakpoint-junctional sequence analysis suggests NHEJ as critical to double-stranded DNA break repair underlying CGR and ecDNA formation. In human melanoma cell lines and PDXs, NHEJ targeting by a DNA-PKCS inhibitor prevents/delays acquired MAPKi resistance by reducing the size of ecDNAs and CGRs early on combination treatment. Thus, targeting the causes of genomic instability prevents acquired resistance., Significance: Acquired resistance often results in heterogeneous, redundant survival mechanisms, which challenge strategies aimed at reversing resistance. Acquired-resistant melanomas recurrently evolve resistance-driving and resistance-specific amplicons via ecDNAs and CGRs, thereby nominating chromothripsis-ecDNA-CGR biogenesis as a resistance-preventive target. Specifically, targeting DNA-PKCS/NHEJ prevents resistance by suppressing ecDNA/CGR rearrangements in MAPKi-treated melanomas. This article is highlighted in the In This Issue feature, p. 799., (©2023 The Authors; Published by the American Association for Cancer Research.)

Background: Melanoma-intrinsic activated β-catenin pathway, the product of the catenin beta 1 (CTNNB1) gene, has been associated with low/absent tumor-infiltrating lymphocytes, accelerated tumor growth, metastases development, and resistance to anti-PD-L1/anti-CTLA-4 agents in mouse melanoma models. Little is known about the association between the adenomatous polyposis coli (APC) and CTNNB1 gene mutations in stage IV melanoma with immunotherapy response and overall survival (OS)., Methods: We examined the prognostic significance of somatic APC/CTNNB1 mutations in the Cancer Genome Atlas Project for Skin Cutaneous Melanoma (TCGA-SKCM) database. We assessed APC/CTNNB1 mutations as predictors of response to immunotherapies in a clinicopathologically annotated metastatic patient cohort from three US melanoma centers., Results: In the TCGA-SKCM patient cohort (n = 434) presence of a somatic APC/CTNNB1 mutation was associated with a worse outcome only in stage IV melanoma (n = 82, median OS of APC/CTNNB1 mutants vs. wild-type was 8.15 vs. 22.8 months; log-rank hazard ratio 4.20, p = 0.011). APC/CTNNB1 mutation did not significantly affect lymphocyte distribution and density. In the 3-melanoma institution cohort, tumor tissues underwent targeted panel sequencing using two standards of care assays. We identified 55 patients with stage IV melanoma and APC/CTNNB1 genetic aberrations (mut) and 169 patients without (wt). At a median follow-up of more than 25 months for both groups, mut compared with wt patients had slightly more frequent (44% vs. 39%) and earlier (66% vs. 45% within six months from original diagnosis of stage IV melanoma) development of brain metastases. Nevertheless, time-to-development of brain metastases was not significantly different between the two groups. Fortunately, mut patients had similar clinical benefits from PD-1 inhibitor-based treatments compared to wt patients (median OS 26.1 months vs. 29.9 months, respectively, log-rank p = 0.23). Less frequent mutations in the NF1, RAC1, and PTEN genes were seen in the mut compared with wt patients from the 3-melanoma institution cohort. Analysis of brain melanoma tumor tissues from a separate craniotomy patient cohort (n = 55) showed that melanoma-specific, activated β-catenin (i.e., nuclear localization) was infrequent (n = 3, 6%) and not prognostic in established brain metastases., Conclusions: APC/CTNNB1 mutations are associated with a worse outcome in stage IV melanoma and early brain metastases independent of tumor-infiltrating lymphocyte density. However, PD1 inhibitor-based treatments provide comparable benefits to both mut and wt patients with stage IV melanoma., (© 2022. The Author(s).)

Abstract: Cutaneous angiosarcomas may express programmed death ligand-1 (PD-L1) and PD-L1 expression, and the presence of tumor-infiltrating lymphocytes (TILs) correlates with outcome. These observations provide a basis for PD-1/PD-L1 inhibitor therapy. Lymphocyte activation gene 3 (LAG-3) is an inhibitory receptor that interacts with the PD-L1 axis and is considered to be a marker of immune exhaustion. The presence of LAG-3-positive lymphocytes in cutaneous angiosarcoma has not been established. We reviewed 10 cases of treatment naive angiosarcoma of skin and superficial soft tissue and assessed for PD-L1 (ZR3) expression, presence of TILs, and expression of CD8, PD1, and LAG-3 by tumor-associated inflammatory cells by immunohistochemistry. All 10 angiosarcomas were positive for PD-L1: 7 with high expression and 3 with low expression. TILs were present in all tumors: brisk in 7 and nonbrisk in 3. CD8 lymphocytes were present in all tumors with a range of 212-1274 cells per square millimeter (mean 557 CD8 cells/mm2). LAG-3-positive lymphocytes were present in 9 of 10 angiosarcomas with a range of 0-728 cells/mm2 (mean 146 LAG-3 cells cells/mm2). The ratio of LAG-3 lymphocytes to CD8 lymphocytes was 0%-59% (mean 27%). The PD1 cell counts were intermediate between CD8 and LAG3 counts. Cutaneous angiosarcomas frequently express PD-L1, have prominent numbers of CD8 positive, and have smaller numbers of LAG-3-positive and PD-1-positive TILs. Our findings provide further evidence of PD-L1 expression in cutaneous angiosarcoma and the promise for immune checkpoint inhibitor therapy., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: IL-2 inducible kinase (ITK) is highly expressed in metastatic melanomas and its inhibition suppresses melanoma cell proliferation. We hypothesize that ibrutinib has a direct antitumor effect in melanoma cell lines and that treatment of metastatic melanomas with ibrutinib induces antitumor responses., Methods: We assessed the ibrutinib effect on melanoma cell proliferation, apoptosis, and motility. Patients with metastatic melanoma refractory to PD-1 and MAPK inhibitors (if BRAFV600-mutant) were treated with ibrutinib, 840 mg PO QD, as part of a phase II clinical trial (clinicaltrials.gov NCT02581930)., Results: Melanoma cell lines frequently express ITK, YES1, and EGFR. Ibrutinib suppressed cell motility and proliferation in most cell lines. Eighteen patients (13 male; median age 63.5 years, range 37-82; 12 with ipilimumab resistance) were enrolled. The most frequent side effects were fatigue (61%), anorexia (50%), hyponatremia (28%), nausea, and vomiting (22% each). No antitumor responses were seen. At a median follow-up of 6 months (0.3-35.8 months), the median progression-free survival was 1.3 months (range 0.2-5.5 months). Fifteen patients were discontinued from the study due to progression, and 14 patients had died from metastatic melanoma. All archived tumors expressed ITK, 41% had no expression of p16 and PTEN, and 61% had absent tumor-infiltrating lymphocytes (TILs). Ibrutinib significantly suppressed proliferating (Ki67+) CD19+ peripheral blood mononuclear cells and had no significant effect on other lymphocyte subsets., Conclusion: Ibrutinib did not induce any meaningful clinical benefit. ITK expression may not be clinically relevant. Treatment-refractory metastatic melanomas have other fundamental defects (i.e. absent PTEN and p16 expression, absent TILs) that may contribute to an adverse prognosis., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Early diagnosis improves melanoma survival, yet the histopathological diagnosis of cutaneous primary melanoma can be challenging, even for expert dermatopathologists. Analysis of epigenetic alterations, such as DNA methylation, that occur in melanoma can aid in its early diagnosis. Using a genome-wide methylation screening, we assessed CpG methylation in a diverse set of 89 primary invasive melanomas, 73 nevi, and 41 melanocytic proliferations of uncertain malignant potential, classified based on interobserver review by dermatopathologists. Melanomas and nevi were split into training and validation sets. Predictive modeling in the training set using ElasticNet identified a 40-CpG classifier distinguishing 60 melanomas from 48 nevi. High diagnostic accuracy (area under the receiver operator characteristic curve = 0.996, sensitivity = 96.6%, and specificity = 100.0%) was independently confirmed in the validation set (29 melanomas, 25 nevi) and other published sample sets. The 40-CpG melanoma classifier included homeobox transcription factors and genes with roles in stem cell pluripotency or the nervous system. Application of the 40-CpG melanoma classifier to the diagnostically uncertain samples assigned melanoma or nevus status, potentially offering a diagnostic tool to assist dermatopathologists. In summary, the robust, accurate 40-CpG melanoma classifier offers a promising assay for improving primary melanoma diagnosis., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Measures of the adaptive immune response have prognostic and predictive associations in melanoma and other cancer types. Specifically, intratumoral T cell density and function have considerable prognostic and predictive value in skin cutaneous melanoma (SKCM). Less is known about the significance of tumor-infiltrating B cells in SKCM. Our goal was to understand the prognostic and predictive value of B cell phenotypic subsets in SKCM using RNA sequencing., Methods: We used our previously published algorithm, V'DJer, to assemble B cell receptor (BCR) repertoires and estimate diversity from short-read RNA sequencing (RNA-seq). We applied machine learning-based cellular phenotype classifiers to measure relative similarity of bulk tumor sample gene expression profiles and different B cell phenotypes. We assessed these aspects of B cell biology in 473 SKCM from the Cancer Genome Atlas Project (TCGA) as well as in RNA-seq data corresponding to tumor samples procured from patients who received CTLA-4 and PD-1 inhibitors for metastatic SKCM., Results: We found that the BCR repertoire was associated with different clinical factors, such as tumor tissue site and sex. However, increased clonality of the BCR repertoire was favorably prognostic in SKCM and was prognostic even after first conditioning on various clinical factors. Mutation burden was not correlated with any BCR measurement, and no specific mutation had an altered BCR repertoire. Lack of an assembled BCR in pre-treatment tumor tissues was associated with a lack of anti-tumor response to a CTLA-4 inhibitor in metastatic SKCM., Conclusions: These findings suggest an important prognostic and predictive role for B cell characteristics in SKCM. This has implications for melanoma immunobiology and potential development of immunogenomics features to predict survival and response to immunotherapy.

Background: Brain metastases are a common cause of disabling neurologic complications and death in patients with metastatic melanoma. Previous studies of nivolumab combined with ipilimumab in metastatic melanoma have excluded patients with untreated brain metastases. We evaluated the efficacy and safety of nivolumab plus ipilimumab in patients with melanoma who had untreated brain metastases., Methods: In this open-label, multicenter, phase 2 study, patients with metastatic melanoma and at least one measurable, nonirradiated brain metastasis (tumor diameter, 0.5 to 3 cm) and no neurologic symptoms received nivolumab (1 mg per kilogram of body weight) plus ipilimumab (3 mg per kilogram) every 3 weeks for up to four doses, followed by nivolumab (3 mg per kilogram) every 2 weeks until progression or unacceptable toxic effects. The primary end point was the rate of intracranial clinical benefit, defined as the percentage of patients who had stable disease for at least 6 months, complete response, or partial response., Results: Among 94 patients with a median follow-up of 14.0 months, the rate of intracranial clinical benefit was 57% (95% confidence interval [CI], 47 to 68); the rate of complete response was 26%, the rate of partial response was 30%, and the rate of stable disease for at least 6 months was 2%. The rate of extracranial clinical benefit was 56% (95% CI, 46 to 67). Treatment-related grade 3 or 4 adverse events were reported in 55% of patients, including events involving the central nervous system in 7%. One patient died from immune-related myocarditis. The safety profile of the regimen was similar to that reported in patients with melanoma who do not have brain metastases., Conclusions: Nivolumab combined with ipilimumab had clinically meaningful intracranial efficacy, concordant with extracranial activity, in patients with melanoma who had untreated brain metastases. (Funded by Bristol-Myers Squibb and the National Cancer Institute; CheckMate 204 ClinicalTrials.gov number, NCT02320058 .).

This study evaluated the safety and clinical benefit of ecromeximab (KW2871) combined with high-dose interferon-α2b (HDI) in patients with metastatic melanoma. We also carried out pharmacokinetic and immune monitoring studies of this combination. This was an open-label, phase 1/2 study of ecromeximab plus HDI in patients with measurable metastatic melanoma. Eligible patients received ecromeximab-HDI combination therapy: ecromeximab administered intravenously once every 2 weeks and HDI at a dose of 20 million units (MU)/m administered intravenously for 5 consecutive days per week for the first 4 weeks (induction phase) and then at 10 MU/m subcutaneously thrice weekly through week 14 (maintenance phase). Patients were treated with combination therapy until disease progression or limiting toxicity. Three dose-escalation cohorts (5, 10, and 20 mg/m) of ecromeximab were planned. Thirty-six evaluable patients were enrolled including six in each of cohorts 1 and 2, and 24 in cohort 3. Median progression-free survival was 2.53 months [95% confidence interval (CI):1.93-3.83] and it was 1.93 months (95% CI: 1.00-3.80) in cohort 3. The median overall survival was 10.28 months (95% CI: 6.93-16.77) and 7.78 months (95% CI: 6.03-13.97) in cohort 3. There was no significant difference in progression-free survival or overall survival by BRAF mutation status. The response rate was 5.6% (95% CI: 0.68-18.7), with two patients showing an objective response (one complete response and one partial response), and the clinical benefit rate was 78% (95% CI: 61-90). Stable disease as best response was observed in 26 (72%) patients including five in each of cohorts 1 and 2, and 16 in cohort 3. Treatment-emergent adverse events considered related to ecromeximab treatment occurred in four (66.7%) patients in cohort 1, five (83.3%) patients in cohort 2, and seven (29.2%) patients in cohort 3. Among TEAEs with a maximum severity of grade 3 or 4, those that occurred only in cohort 3 were related to pain, electrolyte imbalance, blood cell decreases, and allergic reaction. Safety and efficacies considered related to ecromeximab occurred in cohort 3 and included grade 3 hypersensitivity [one (4.2%)] and grade 2 hypotension [one (4.2%)]. Regimen-limiting toxicities occurred in two (8.3%) patients in cohort 3: hypersensitivity (with hypertension, supraventricular tachycardia, bronchospasm, chills, and dyspnea) and hypotension. One patient out of 31 examined showed a low-level transient positivity for human antichimeric antibodies against ecromeximab. Pharmacokinetic measurements by enzyme-linked immunosorbent assay determined that administration of HDI does not influence serum levels of ecromeximab at 5, 10, and 20 mg/m dose levels. Ecromeximab in combination with HDI was generally well tolerated in patients with metastatic melanoma and has shown low immunogenicity. However, the clinical activity was limited, suggesting that future development of this combination should be deprioritized and that other combinations, such as with immune checkpoint inhibitors, should be considered.

Background: Patients with melanoma that progresses on ipilimumab and, if BRAF(V600) mutant-positive, a BRAF or MEK inhibitor or both, have few treatment options. We assessed the efficacy and safety of two pembrolizumab doses versus investigator-choice chemotherapy in patients with ipilimumab-refractory melanoma., Methods: We carried out a randomised phase 2 trial of patients aged 18 years or older from 73 hospitals, clinics, and academic medical centres in 12 countries who had confirmed progressive disease within 24 weeks after two or more ipilimumab doses and, if BRAF(V600) mutant-positive, previous treatment with a BRAF or MEK inhibitor or both. Patients had to have resolution of all ipilimumab-related adverse events to grade 0-1 and prednisone 10 mg/day or less for at least 2 weeks, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and at least one measurable lesion to be eligible. Using a centralised interactive voice response system, we randomly assigned (1:1:1) patients in a block size of six to receive intravenous pembrolizumab 2 mg/kg or 10 mg/kg every 3 weeks or investigator-choice chemotherapy (paclitaxel plus carboplatin, paclitaxel, carboplatin, dacarbazine, or oral temozolomide). Randomisation was stratified by ECOG performance status, lactate dehydrogenase concentration, and BRAF(V600) mutation status. Individual treatment assignment between pembrolizumab and chemotherapy was open label, but investigators and patients were masked to assignment of the dose of pembrolizumab. We present the primary endpoint at the prespecified second interim analysis of progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT01704287. The study is closed to enrolment but continues to follow up and treat patients., Findings: Between Nov 30, 2012, and Nov 13, 2013, we enrolled 540 patients: 180 patients were randomly assigned to receive pembrolizumab 2 mg/kg, 181 to receive pembrolizumab 10 mg/kg, and 179 to receive chemotherapy. Based on 410 progression-free survival events, progression-free survival was improved in patients assigned to pembrolizumab 2 mg/kg (HR 0·57, 95% CI 0·45-0·73; p<0·0001) and those assigned to pembrolizumab 10 mg/kg (0·50, 0·39-0·64; p<0·0001) compared with those assigned to chemotherapy. 6-month progression-free survival was 34% (95% CI 27-41) in the pembrolizumab 2 mg/kg group, 38% (31-45) in the 10 mg/kg group, and 16% (10-22) in the chemotherapy group. Treatment-related grade 3-4 adverse events occurred in 20 (11%) patients in the pembrolizumab 2 mg/kg group, 25 (14%) in the pembrolizumab 10 mg/kg group, and 45 (26%) in the chemotherapy group. The most common treatment-related grade 3-4 adverse event in the pembrolizumab groups was fatigue (two [1%] of 178 patients in the 2 mg/kg group and one [<1%] of 179 patients in the 10 mg/kg group, compared with eight [5%] of 171 in the chemotherapy group). Other treatment-related grade 3-4 adverse events include generalised oedema and myalgia (each in two [1%] patients) in those given pembrolizumab 2 mg/kg; hypopituitarism, colitis, diarrhoea, decreased appetite, hyponatremia, and pneumonitis (each in two [1%]) in those given pembrolizumab 10 mg/kg; and anaemia (nine [5%]), fatigue (eight [5%]), neutropenia (six [4%]), and leucopenia (six [4%]) in those assigned to chemotherapy., Interpretation: These findings establish pembrolizumab as a new standard of care for the treatment of ipilimumab-refractory melanoma., Funding: Merck Sharp & Dohme., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Purpose: IL2 inducible T-cell kinase (ITK) promoter CpG sites are hypomethylated in melanomas compared with nevi. The expression of ITK in melanomas, however, has not been established and requires elucidation., Experimental Design: An ITK-specific monoclonal antibody was used to probe sections from deidentified, formalin-fixed paraffin-embedded tumor blocks or cell line arrays and ITK was visualized by IHC. Levels of ITK protein differed among melanoma cell lines and representative lines were transduced with four different lentiviral constructs that each contained an shRNA designed to knockdown ITK mRNA levels. The effects of the selective ITK inhibitor BI 10N on cell lines and mouse models were also determined., Results: ITK protein expression increased with nevus to metastatic melanoma progression. In melanoma cell lines, genetic or pharmacologic inhibition of ITK decreased proliferation and migration and increased the percentage of cells in the G0-G1 phase. Treatment of melanoma-bearing mice with BI 10N reduced growth of ITK-expressing xenografts or established autochthonous (Tyr-Cre/Pten(null)/Braf(V600E)) melanomas., Conclusions: We conclude that ITK, formerly considered an immune cell-specific protein, is aberrantly expressed in melanoma and promotes tumor development and progression. Our finding that ITK is aberrantly expressed in most metastatic melanomas suggests that inhibitors of ITK may be efficacious for melanoma treatment. The efficacy of a small-molecule ITK inhibitor in the Tyr-Cre/Pten(null)/Braf(V600E) mouse melanoma model supports this possibility., (©2015 American Association for Cancer Research.)

Advances in the biology of melanoma have provided insights about chemoresistance and its genetic heterogeneity in parallel with advances in drug design, culminating in recent major treatment breakthroughs. Although clinical benefit of targeted therapies has been unquestionable, future advances are only possible if we understand the interplay between genetic aberrations and role of other crucial nongenetic changes yet to be identified by such projects as the Cancer Genome Atlas Project in Melanoma. Combination therapies, either among small molecule inhibitors themselves and/or with immunotherapies, may be the optimal strategy to prevent development of drug resistance inherently linked with such targeted therapies., (Copyright © 2015 Elsevier Inc. All rights reserved.)

DNA methylation studies have elucidated a methylation signature distinguishing primary melanomas from benign nevi and provided new insights about genes that may be important in melanoma development. However, it is unclear whether methylation differences among primary melanomas are related to tumor pathologic features with known clinical significance. We utilized the Illumina GoldenGate Cancer Panel array to investigate the methylation profiles of 47 primary cutaneous melanomas. Arraywide methylation patterns revealed a positive association of methylation with Breslow thickness and mutated BRAF, a negative association with mitotic rate, and a weak association with ulceration. Hierarchical clustering on CpG sites exhibiting the most variable methylation (n = 235) divided the melanoma samples into three clusters, including a highly methylated cluster that was positively associated with Breslow thickness and an intermediately methylated cluster associated with Breslow thickness and mitotic rate. Our findings provide support for the existence of methylation-defined subsets in melanomas with increased methylation associated with Breslow thickness., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

PURPOSE To assess pharmacodynamic effects and intrinsic and acquired resistance mechanisms of the BRAF inhibitor vemurafenib in BRAF(V600)-mutant melanoma, leading to an understanding of the mechanism of action of vemurafenib and ultimately to optimization of metastatic melanoma therapy. METHODS In the phase II clinical study NP22657 (BRIM-2), patients received oral doses of vemurafenib (960 mg twice per day). Serial biopsies were collected to study changes in mitogen-activated protein kinase (MAPK) signaling, cell-cycle progression, and factors causing intrinsic or acquired resistance by immunohistochemistry, DNA sequencing, or somatic mutation profiling. Results Vemurafenib inhibited MAPK signaling and cell-cycle progression. An association between the decrease in extracellular signal-related kinase (ERK) phosphorylation and objective response was observed in paired biopsies (n = 22; P = .013). Low expression of phosphatase and tensin homolog showed a modest association with lower response. Baseline mutations in MEK1(P124) coexisting with BRAF(V600) were noted in seven of 92 samples; their presence did not preclude objective tumor responses. Acquired resistance to vemurafenib associated with reactivation of MAPK signaling as observed by elevated ERK1/2 phosphorylation levels in progressive lesions and the appearance of secondary NRAS(Q61) mutations or MEK1(Q56P) or MEK1(E203K) mutations. These two activating MEK1 mutations had not previously been observed in vivo in biopsies of progressive melanoma tumors. CONCLUSION Vemurafenib inhibits tumor proliferation and oncogenic BRAF signaling through the MAPK pathway. Acquired resistance results primarily from MAPK reactivation driven by the appearance of secondary mutations in NRAS and MEK1 in subsets of patients. The data suggest that inhibition downstream of BRAF should help to overcome acquired resistance.

Malignant melanoma is characterized by a propensity for early lymphatic and hematogenous spread. The hypoxia-inducible factor (HIF) family of transcription factors is upregulated in melanoma by key oncogenic drivers. HIFs promote the activation of genes involved in cancer initiation, progression, and metastases. Hypoxia has been shown to enhance the invasiveness and metastatic potential of tumor cells by regulating the genes involved in the breakdown of the ECM as well as genes that control motility and adhesion of tumor cells. Using a Pten-deficient, Braf-mutant genetically engineered mouse model of melanoma, we demonstrated that inactivation of HIF1α or HIF2α abrogates metastasis without affecting primary tumor formation. HIF1α and HIF2α drive melanoma invasion and invadopodia formation through PDGFRα and focal adhesion kinase-mediated (FAK-mediated) activation of SRC and by coordinating ECM degradation via MT1-MMP and MMP2 expression. These results establish the importance of HIFs in melanoma progression and demonstrate that HIF1α and HIF2α activate independent transcriptional programs that promote metastasis by coordinately regulating cell invasion and ECM remodeling.

Metastatic melanoma is one of the most aggressive forms of cutaneous cancers. Although recent therapeutic advances have prolonged patient survival, the prognosis remains dismal. C-MER proto-oncogene tyrosine kinase (MERTK) is a receptor tyrosine kinase with oncogenic properties that is often overexpressed or activated in various malignancies. Using both protein immunohistochemistry and microarray analyses, we demonstrate that MERTK expression correlates with disease progression. MERTK expression was highest in metastatic melanomas, followed by primary melanomas, while the lowest expression was observed in nevi. Additionally, over half of melanoma cell lines overexpressed MERTK compared with normal human melanocytes; however, overexpression did not correlate with mutations in BRAF or RAS. Stimulation of melanoma cells with the MERTK ligand GAS6 resulted in the activation of several downstream signaling pathways including MAPK/ERK, PI3K/AKT, and JAK/STAT. MERTK inhibition via shRNA reduced MERTK-mediated downstream signaling, reduced colony formation by up to 59%, and diminished tumor volume by 60% in a human melanoma murine xenograft model. Treatment of melanoma cells with UNC1062, a novel MERTK-selective small-molecule tyrosine kinase inhibitor, reduced activation of MERTK-mediated downstream signaling, induced apoptosis in culture, reduced colony formation in soft agar, and inhibited invasion of melanoma cells. This work establishes MERTK as a therapeutic target in melanoma and provides a rationale for the continued development of MERTK-targeted therapies.

Purpose: We tested the hypothesis that the combination of tremelimumab and interferon alfa-2b acting via different and possibly synergistic mechanisms would overcome tumor immune tolerance and lead to significant and durable clinical responses., Patients and Methods: We conducted a phase II study in which patients were administered tremelimumab 15 mg/kg/course (three cycles [one cycle = 4 weeks]) intravenously every 12 weeks. High-dose interferon alfa-2b (HDI) was administered concurrently, including intravenous induction at 20 MU/m2/d for 5 d/wk for 4 weeks followed by maintenance at 10 MU/m2/d subcutaneously three times a week for 8 weeks per course. From course 2 onward, HDI maintenance was administered subcutaneously., Results: Thirty-seven patients with American Joint Committee on Cancer stage IV (9M1a, 6M1b, and 22M1c) were enrolled. Two patients had previously treated brain metastases. Grades 3 and 4 toxicities included neutropenia (six patients; 17%), diarrhea/colitis (four patients; 11%), liver enzyme increase (four patients; 11%), rash (four patients; 11%), fatigue (15 patients; 40%), and anxiety/depression (five patients; 14%). Response data were available for 35 patients. The best objective response rate (RR; Response Evaluation Criteria in Solid Tumors) by intention to treat was 24% (90% CI, 13% to 36%; four complete responses [CRs] and five partial responses [PRs] that lasted 6, 6, > 12, > 14, > 18, 20, > 28, 30, and > 37 months, respectively). Fourteen patients (38%) had stable disease (SD) that lasted 1.5 to 21 months. The median progression-free survival was 6.4 months (95% CI, 3.3 to 12.1 months). The median overall survival (OS) was 21 months (95% CI, 9.5 to not reached). There was a weak association between therapy-induced autoimmunity and clinical benefits (CR/PR/SD; P = .0059), baseline C-reactive protein (CRP) less than or equal to 2.7× the upper limit of normal and clinical benefits (P = .0494) and improved probability of survival (P = .0032), and baseline lymphocyte count of at least 1,000/μL and response (CR/PR; P = .0183) and clinical benefits (CR/PR/SD; P = .0255). Biomarker associations were not significant after adjustment for multiple comparisons., Conclusion: HDI can be administered combined with tremelimumab with acceptable toxicity and promising durable antitumor efficacy that warrant further testing in a randomized trial.

Purpose: Immunotherapy has a long history with striking but limited success in patients with melanoma. To date, interleukin-2 and interferon-alfa2b are the only approved immunotherapeutic agents for melanoma in the United States., Design: Tumor evasion of host immune responses, and strategies for overcoming tumor-induced immunosuppression are reviewed. Several novel immunotherapies currently in worldwide phase III clinical testing for melanoma are discussed., Results: The limitations of immunotherapy for melanoma stem from tumor-induced mechanisms of immune evasion that render the host tolerant of tumor antigens. For example, melanoma inhibits the maturation of antigen-presenting cells, preventing full T-cell activation and downregulating the effector antitumor immune response. New immunotherapies targeting critical regulatory elements of the immune system may overcome tolerance and promote a more effective antitumor immune response. These include monoclonal antibodies that block the cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and toll-like receptor 9 (TLR9) agonists. Blockade of CTLA4 prevents inhibitory signals that downregulate T-cell activation. TLR9 agonists stimulate dendritic cell maturation and ultimately induce a more effective immune response. These approaches have been shown to stimulate acute immune activation with concomitant appearance of transient adverse events mediated by the immune system. The pattern and duration of immune responses associated with these new modalities differ from those associated with cytokines and cytotoxic agents. In addition, vaccines are being developed that may ultimately target melanoma either alone or in combination with these immunomodulatory therapies., Conclusion: The successes of cytokine and interferon therapy of melanoma, coupled with an array of new approaches, are generating new enthusiasm for the immunotherapy of melanoma.

In patients with stage IIB-III disease, adjuvant high-dose interferon-alpha2b has shown clinical benefit, although metastatic melanoma is currently without any known survival-prolonging therapy. Angiogenesis has been considered important in melanoma progression, and endostatin is an angiogenesis inhibitor with antitumor activity that has shown promising results in murine model systems, prompting investigation of a formulation of rh-Endostatin (EntreMed, Rockville, Maryland, USA) alone and with interferon in metastatic melanoma. Patients were randomly assigned to receive interferon alpha2b (Schering-Plough) 10 million units/m(2) subcutaneously three times a week plus rh-Endostatin 45 mg/m(2) subcutaneously every 12 h (arm A) vs. rh-Endostatin alone (arm B). Twenty-one patients (age range 31-77 years, median age 54, 12 men and nine women, 17 cutaneous, and four ocular melanomas) were enrolled. No antitumor responses were observed, and no significant differences were noted in time to progression or overall survival. Two patients had stable disease enduring more than 30 weeks on treatment. Serum endostatin levels increased significantly 4 weeks after treatment in both groups. Basic fibroblast growth factor levels in urine were significantly lower following treatment in patients on arm B (P=0.043). The percentage of circulating endothelial cells was increased in five evaluable patients 4 weeks after treatment. Low titer (

Purpose: Adjuvant high-dose interferon-alfa-2b (HDI) improves disease-free and overall survival in patients with high-risk melanoma. However, its mechanism of action is largely unknown. Therefore, HDI was investigated in the neoadjuvant setting to assess clinical and pathologic responses after 4 weeks of HDI and to perform immunohistochemical evaluation of immune cell subsets and melanoma-associated antigens., Patients and Methods: Patients with palpable regional lymph node metastases from melanoma (American Joint Committee on Cancer stage IIIB-C) underwent surgical biopsy at study entry and then received standard intravenous HDI (20 million units/m2, 5 days per week) for 4 weeks followed by complete lymphadenectomy and standard maintenance subcutaneous HDI (10 million units/m2 3 times per week) for 48 weeks. Biopsy samples were obtained before and after intravenous HDI and subjected to immunohistochemical analysis as well as routine pathologic study., Results: Twenty patients were enrolled, and biopsy samples were informative for 17. Eleven patients (55%) demonstrated objective clinical response, and 3 patients (15%) had complete pathologic response. At a median follow-up of 18.5 months (range, 7 months to 50 months) 10 patients had no evidence of recurrent disease. Clinical responders had significantly greater increases in endotumoral CD11c+ and CD3+ cells and significantly greater decreases in endotumoral CD83+ cells compared with nonresponders. No changes in the expression of melanoma-associated lineage antigens, tumor cell proliferation, angiogenesis, or apoptosis were evident., Conclusion: Neoadjuvant HDI is highly effective for the treatment of palpable stage IIIB-C melanoma, and the findings of this study implicate an indirect immunomodulatory mechanism rather than a direct antitumor mechanism.