Circulating Cell-Free SHOX2 DNA Methylation Is a Predictive, Prognostic, and Monitoring Biomarker in Adjuvant and Palliative Anti-PD-1-Treated Melanoma.

BACKGROUND: The majority of metastatic melanoma patients initially do not respond or acquire resistance to anti-programmed cell death 1 (PD-1) immunotherapy. Liquid biopsy biomarkers might provide useful early response information and allow for personalized treatment decisions. METHODS: We prospectively assessed circulating cell-free SHOX2 DNA methylation (SHOX2 ccfDNAm) levels and their dynamic changes in blood plasma of melanoma patients by quantitative methylation-specific polymerase chain reaction. Patients were treated with either palliative (n = 42) or adjuvant (n = 55) anti-PD-1 immunotherapy. Moreover, we included n = 126 control patients without evidence of malignant disease. We analyzed SHOX2 ccfDNAm status prior to and 4 weeks after palliative treatment initiation with regard to outcome [objective response, progression-free survival (PFS), and overall survival (OS)]. In the adjuvant setting, we associated longitudinal SHOX2 ccfDNAm status with disease recurrence. RESULTS: Sensitivity was 60% with 25/42 melanoma patients showing increased SHOX2 ccfDNAm levels, whereas specificity was 98% with 123/126 (P < 0.001) control patients having SHOX2 ccfDNAm levels below cut-off. Pretreatment SHOX2 ccfDNAm status did not correlate with outcome; however, SHOX2 ccfDNAm negativity 4 weeks after palliative treatment initiation was strongly associated with improved survival [PFS: hazard ratio (HR) = 0.25, P = 0.002; OS: HR = 0.12, P = 0.007]. Pretreatment positive patients who reached SHOX2 ccfDNAm clearance after 4 weeks of immunotherapy showed an exceptionally beneficial outcome. SHOX2 ccfDNAm testing allowed for an early detection of distant metastases in adjuvant-treated melanoma patients. CONCLUSIONS: Our study suggests SHOX2 ccfDNAm to be an early predictor of outcome in anti-PD-1 treated melanoma patients. SHOX2 ccfDNAm testing may aid individualized treatment decision-making.

Adult-Onset Neurodegeneration in Nucleotide Excision Repair Disorders (NERDND ): Time to Move Beyond the Skin.

BACKGROUND: Variants in genes of the nucleotide excision repair (NER) pathway have been associated with heterogeneous clinical presentations ranging from xeroderma pigmentosum to Cockayne syndrome and trichothiodystrophy. NER deficiencies manifest with photosensitivity and skin cancer, but also developmental delay and early-onset neurological degeneration. Adult-onset neurological features have been reported in only a few xeroderma pigmentosum cases, all showing at least mild skin manifestations. OBJECTIVE: The aim of this multicenter study was to investigate the frequency and clinical features of patients with biallelic variants in NER genes who are predominantly presenting with neurological signs. METHODS: In-house exome and genome datasets of 14,303 patients, including 3543 neurological cases, were screened for deleterious variants in NER-related genes. Clinical workup included in-depth neurological and dermatological assessments. RESULTS: We identified 13 patients with variants in ERCC4 (n = 8), ERCC2 (n = 4), or XPA (n = 1), mostly proven biallelic, including five different recurrent and six novel variants. All individuals had adult-onset progressive neurological deterioration with ataxia, dementia, and frequently chorea, neuropathy, and spasticity. Brain magnetic resonance imaging showed profound global brain atrophy in all patients. Dermatological examination did not show any skin cancer or pronounced ultraviolet damage. CONCLUSIONS: We introduce NERDND as adult-onset neurodegeneration (ND ) within the spectrum of autosomal recessive NER disorders (NERD). Our study demonstrates that NERDND is probably an underdiagnosed cause of neurodegeneration in adulthood and should be considered in patients with overlapping cognitive and movement abnormalities. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

S1 Guidelines for the Kaposi Sarcoma.

Kaposi's sarcoma (KS) is a rare, malignant, multilocular vascular disease originating from lymphatic endothelial cells that can primarily affect the skin and mucous membranes, but also the lymphatic system and internal organs such as the gastrointestinal tract, lungs or liver. Five epidemiological subtypes of KS with variable clinical course and prognosis are distinguished, with increased incidence in specific populations: (1) Classical KS, (2) Iatrogenic KS in immunosuppression, (3) Endemic (African) lymphadenopathic KS, (4) Epidemic, HIV-associated KS and KS associated with immune reconstitution inflammatory syndrome (IRIS), and (5) KS in men who have sex with men (MSM) without HIV infection. This interdisciplinary guideline summarizes current practice-relevant recommendations on diangostics and therapy of the different forms of KS. The recommendations mentioned in this short guideline are elaborated in more detail in the extended version of the guideline (online format of the JDDG).

S1-Leitlinie: Kaposi-Sarkom.

Das Kaposi-Sarkom (KS) ist eine seltene, maligne, von lymphatischen Endothelzellen ausgehende, multilokuläre Gefäßerkrankung, die vor allem Haut und Schleimhäute, aber auch das lymphatische System und innere Organe wie den Gastrointestinaltrakt, die Lunge oder die Leber befallen kann. Fünf epidemiologische Subtypen des KS mit variablem klinischem Verlauf und unterschiedlicher Prognose werden unterschieden, die in spezifischen Populationen vermehrt auftreten: (1) klassisches KS, (2) iatrogenes KS bei Immunsuppression, (3) endemisches (afrikanisches) lymphadenopathisches KS, (4) epidemisches, HIV-assoziiertes KS und mit einem Immunrekonstitutions-Inflammations-Syndrom (IRIS) assoziiertes KS und (5) KS bei Männern, die Sex mit Männern haben (MSM) ohne HIV-Infektion. Diese interdisziplinäre Leitlinie fasst aktuelle praxisrelevante Empfehlungen zu Diagnostik und Therapie der verschiedenen Formen des KS zusammen. Die in dieser Kurzleitlinie genannten Empfehlungen werden in der Langfassung der Leitlinie (Online-Version des JDDG) detaillierter ausgeführt.

Cardiac MRI Depicts Immune Checkpoint Inhibitor-induced Myocarditis: A Prospective Study.

Background Immune checkpoint inhibitors (ICIs) for cancer treatment are associated with a spectrum of immune-related adverse events, including ICI-induced myocarditis; however, the extent of subclinical acute cardiac effects related to ICI treatment is unclear. Purpose To explore the extent of cardiac injury and inflammation related to ICI therapy that can be detected with use of cardiac MRI. Materials and Methods In this prospective study from November 2019 to April 2021, oncologic participants, without known underlying structural heart disease or cardiac symptoms, underwent multiparametric cardiac MRI before planned ICI therapy (baseline) and 3 months after starting ICI therapy (follow-up). The cardiac MRI protocol incorporated assessment of cardiac function, including systolic myocardial strain, myocardial edema, late gadolinium enhancement (LGE), T1 and T2 relaxation times, and extracellular volume fraction. The paired t test, Wilcoxon signed-rank test, and McNemar test were used for intraindividual comparisons. Results Twenty-two participants (mean age ± standard deviation, 65 years ± 14; 13 men) were evaluated, receiving a median of four infusions of ICI therapy (interquartile range, four to six infusions). Compared with baseline MRI, participants displayed increased markers of diffuse myocardial edema at follow-up (T1 relaxation time, 972 msec ± 26 vs 1006 msec ± 36 [P < .001]; T2 relaxation time, 54 msec ± 3 vs 58 msec ± 4 [P < .001]; T2 signal intensity ratio, 1.5 ± 0.3 vs 1.7 ± 0.3 [P = .03]). Left ventricular average systolic longitudinal strain had decreased at follow-up MRI (-23.4% ± 4.8 vs -19.6% ± 5.1, respectively; P = .005). New nonischemic LGE lesions were prevalent in two of 22 participants (9%). Compared with baseline, small pericardial effusions were more evident at follow-up (one of 22 participants [5%] vs 10 of 22 [45%]; P = .004). Conclusion In participants who received immune checkpoint inhibitor therapy for cancer treatment, follow-up cardiac MRI scans showed signs of systolic dysfunction and increased parameters of myocardial edema and inflammation. © RSNA, 2021 Online supplemental material is available for this article.

Talimogene laherparepvec treatment to overcome loco-regional acquired resistance to immune checkpoint blockade in tumor stage IIIB-IV M1c melanoma patients.

BACKGROUND: Resistance to immune checkpoint blockade and targeted therapy in melanoma patients is currently one of the major clinical challenges. With the approval of talimogene laherparepvec (T-VEC), oncolytic viruses are now in clinical practice for locally advanced or non-resectable melanoma. Here, we describe the usage of T-VEC in stage IVM1b-M1c melanoma patients, who achieved complete remission or stable disease upon systemic treatment but suffered from a loco-regional recurrence. To our knowledge, there are no case reports so far describing T-VEC as a means to overcome acquired resistance to immune checkpoint blockade or targeted therapy. METHODS: All melanoma patients in our department treated with T-VEC in the period of 2016-2018 were evaluated retrospectively. Data on clinicopathological characteristics, treatment response, and toxicity were analyzed. RESULTS: Fourteen melanoma patients were treated with T-VEC in our center. Six patients (43%) received T-VEC first-line. In eight patients (57%), T-VEC followed a prior systemic therapy. Three patients with M1b stage and one patient with M1c stage melanoma were treated with T-VEC. These patients suffered from loco-regional progress, whilst distant metastases had regressed during prior systemic treatment. 64% of patients showed a benefit from therapy with T-VEC. The durable response rate was 36%. CONCLUSION: T-VEC represents an effective and tolerable treatment option. This is true not only for loco-regionally advanced melanoma patients, but also for patients with stable or regressive systemic metastases who develop loco-regionally acquired resistance upon treatment with immune checkpoint blockade or targeted therapy. A sensible selection of suitable patients seems to be crucial.

DNA methylation of GITR, OX40, 4-1BB, CD27 , and CD40 correlates with BAP1 aberrancy and prognosis in uveal melanoma.

Uveal melanoma represents an aggressive tumor that responds mostly poorly to established melanoma treatments. Comprehensive methylation profiling of the next-generation immunotherapeutic target genes, for example, members of the tumor necrosis factor receptor superfamily, might allow for the development of companion predictive biomarkers. We have analyzed CpG sites within the immune checkpoint genes GITR, OX40, 4-1BB, CD 27, and CD40 probed by the Illumina Infinium HumanMethylation450 BeadChip in N = 80 uveal melanomas included in The Cancer Genome Atlas with regard to BAP1 aberrancy, mRNA expression, and overall survival. In all analyzed immune checkpoint genes, BAP1 aberrancy was associated with decreased CpG methylation levels. We identified specific CpG sites that significantly correlated with BAP1 aberrancy, mRNA expression levels, and overall survival. Our results suggest epigenetic regulation of the analyzed immune checkpoint genes via DNA methylation in uveal melanoma and provide rationale for methylation testing in biomarker programs in clinical trials.

Manifestation of subacute cutaneous lupus erythematosus during treatment with anti-PD-1 antibody cemiplimab - a case report.

Introduction: The anti-programmed cell death protein 1 (PD-1) antibody cemiplimab has shown promising results in the treatment of unresectable or metastatic squamous cell carcinoma, however, frequently leads to immune-related adverse events limiting therapy efficacy. Although cutaneous side effects are common, only very few cases of cutaneous lupus erythematosus have been reported under anti-PD-1 immunotherapy. So far, no case of cutaneous lupus has been described under treatment with cemiplimab. Case report: For the first time, we report the case of a patient with advanced squamous cell carcinoma, who developed clinical and histological findings in sun-exposed skin that were consistent with anti-SS-A/Ro antibody-positive subacute cutaneous lupus erythematosus (SCLE) under treatment with cemiplimab. Additionally, laboratory chemical analyses revealed a severe immune-related hepatitis without clinical symptoms. Both, the SCLE and the hepatitis, resolved after the administration of topical and systemic steroids and the discontinuation of anti-PD-1 therapy. Conclusion: Treatment with cemiplimab can be associated with the appearance of cutaneous lupus erythematosus in sun-exposed areas. Application of topical and systemic glucocorticoids can lead to a rapid resolution of the skin eruptions. Moreover, our case illustrates the possibility of simultaneously occurring severe immune-related adverse events. This highlights the importance of additional diagnostics to avoid overlooking additional immune-related adverse events.

[Melanoma microenvironment-impact of modern therapies]. / Tumormikromilieu des Melanoms ­ Einfluss moderner Therapien.

BACKGROUND: A considerable proportion of patients with advanced melanoma succumb to metastatic disease despite the initial success of modern therapies. OBJECTIVES: An overview of the melanoma tumor microenvironment with special focus on approved therapies and new innovative strategies is given. METHODS: Current clinical trials and scientific insights concerning the impact of the tumor microenvironment on progression and therapy of advanced melanoma are reviewed and discussed. RESULTS: The tumor microenvironment with its manifold components and interactions plays a major role in the treatment of malignant melanoma. CONCLUSION: Innovative new strategies that target an immunosuppressive microenvironment may improve the therapeutic efficacy of current treatment of advanced melanoma.

DNA methylation regulates TIGIT expression within the melanoma microenvironment, is prognostic for overall survival, and predicts progression-free survival in patients treated with anti-PD-1 immunotherapy.

BACKGROUND: TIGIT is an immune checkpoint under investigation as therapeutic target. Understanding the regulation of TIGIT on an epigenetic level might support the development of companion biomarkers. METHODS: We correlated TIGIT DNA methylation of single CpG sites with gene expression, signatures of immune infiltrates and interferon-γ, and survival in melanoma. We further analyzed methylation levels in immune cell subsets, melanocyte and melanoma cell lines. TIGIT expression patterns within components of the melanoma microenvironment were analyzed by single cell sequencing. We used quantitative methylation-specific PCR, flow cytometry, and immunohistochemistry for correlations between expression and methylation and to assess the effect of pharmacological demethylation of melanoma cells treated with 5-aza-2-deoxycytidine (decitabine). Finally, we investigated the association of patients' survival with TIGIT mRNA and methylation. RESULTS: Depending on the sequence context of the analyzed CpG site, we found a cell type-specific TIGIT gene locus methylation pattern and significant correlations of TIGIT methylation with mRNA expression, an interferon γ signature, and distinct immune cell infiltrates, including TIGIT+ lymphocytes. We detected a melanoma cell-intrinsic TIGIT protein expression. Pharmacological demethylation of the A375 melanoma cell line led to a constitutive TIGIT expression. Low promoter flank methylation and high mRNA expression was associated with patients' prognosis and predicted progression-free survival in patients treated with anti-PD-1 immunotherapy. A high TIGIT+ lymphocyte score was associated with better progression-free survival under anti-PD-1 immunotherapy. CONCLUSIONS: Our data demonstrate an epigenetic regulation of TIGIT expression via DNA methylation within the melanoma microenvironment. TIGIT DNA methylation and expression may serve as predictive biomarkers in the context of immunotherapies in melanoma.

Grzybowski's Generalized Eruptive Keratoacanthomas in a Patient with Terminal Kidney Disease-An Unmet Medical Need Equally Ameliorated by Topical Imiquimod Cream and Lapacho Tea Wraps: A Case Report.

INTRODUCTION: Development of singular keratoacanthoma (KA) is generally considered a benign condition as it has a tendency to regress spontaneously in spite of histological similarity to squamous cell carcinoma. Most KAs undergo excision to rule out differential diagnoses. Several alternative treatment modalities (keratinolytic, ablative, immunomodulating, antiproliferative, or targeted therapy) have been described in the past with varying success, underlining the therapeutic challenges associated with large or multiple lesions. Isomorphic response (Koebner phenomenon) may limit the efficacy of ablative options, and comorbidity may limit the use of systemic treatments. Less aggressive topical immunomodulatory treatment options represent an alternative with varying therapeutic success. CASE REPORT: Here, we describe the clinical course of a 51-year-old male patient with terminal kidney disease who suffered from the rare benign pruritic condition of Grzybowski's generalized eruptive keratoacanthomas (GEKA) and experienced a significant reduction of lesions and symptoms upon topical therapy with imiquimod 5% cream and lapacho tea dressings alike. CONCLUSIONS: Very little is known about the potential antiinflammatory or antiproliferative effects on the epidermis of the popular phytotherapeutic agent lapacho tea. More studies are warranted considering both the etiology and treatment of GEKA and topical use of phytotherapeutics in dermatology in general. Management of large or multiple KAs remains challenging.

Deep Learning-Based Body Composition Analysis Predicts Outcome in Melanoma Patients Treated with Immune Checkpoint Inhibitors.

Previous studies suggest an impact of body composition on outcome in melanoma patients. We aimed to determine the prognostic value of CT-based body composition assessment in patients receiving immune checkpoint inhibitor therapy for treatment of metastatic disease using a deep learning approach. One hundred seven patients with staging CT examinations prior to initiation of checkpoint inhibition between January 2013 and August 2019 were retrospectively evaluated. Using an automated deep learning-based body composition analysis pipeline, parameters for estimation of skeletal muscle mass (skeletal muscle index, SMI) and adipose tissue compartments (visceral adipose tissue index, VAI; subcutaneous adipose tissue index, SAI) were derived from staging CT. The cohort was binarized according to gender-specific median cut-off values. Patients below the median were defined as having low SMI, VAI, or SAI, respectively. The impact on outcome was assessed using the Kaplan-Meier method with log-rank tests. A multivariable logistic regression model was built to test the impact of body composition parameters on 3-year mortality. Patients with low SMI displayed significantly increased 1-year (25% versus 9%, p = 0.035), 2-year (32% versus 13%, p = 0.017), and 3-year mortality (38% versus 19%, p = 0.016). No significant differences with regard to adipose tissue compartments were observed (3-year mortality: VAI, p = 0.448; SAI, p = 0.731). On multivariable analysis, low SMI (hazard ratio (HR), 2.245; 95% confidence interval (CI), 1.005-5.017; p = 0.049), neutrophil-to-lymphocyte ratio (HR, 1.170; 95% CI, 1.076-1.273; p < 0.001), and Karnofsky index (HR, 0.965; 95% CI, 0.945-0.985; p = 0.001) remained as significant predictors of 3-year mortality. Lowered skeletal muscle index as an indicator of sarcopenia was associated with worse outcome in patients with metastatic melanoma receiving immune checkpoint inhibitor therapy.

Outcome of melanoma patients with elevated LDH treated with first-line targeted therapy or PD-1-based immune checkpoint inhibition.

BACKGROUND: Elevated lactate dehydrogenase (LDH) is a known predictive and prognostic factor for a poor outcome in patients with metastatic melanoma. It is unclear whether first-line targeted therapy (TT) or immune checkpoint inhibition (ICI) is more beneficial in melanoma patients with elevated LDH because prospective studies in this area are lacking. METHODS: This multicentre retrospective cohort study was conducted at 25 melanoma centres worldwide to analyse progression-free survival (PFS) and overall survival (OS) among melanoma patients with elevated LDH. The role of confounders was addressed by using inverse probability of treatment weighting. RESULTS: Among 173 BRAFV600-mutant patients, PFS at 12 months in the TT group was 22% compared with 52% in the combined anti-PD-1 and anti-CTLA-4 group (HR 0.6, 95% CI 0.4-1.0, p = 0.07) and 18% in the anti-PD-1 monotherapy group (HR 1.8, 95% CI 1.2-2.8, p = 0.003). Twelve months' OS was 48% in the TT group compared with 83% in the combined anti-PD-1 and anti-CTLA-4 group (HR 0.5, 95% CI 0.3-1.0, p = 0.03) and 50% in the anti-PD-1 monotherapy group (HR 1.2, 95% CI 0.8-2.0, p = 0.37). The ORR in the TT group was 63%, compared with 55% and 20% in the combined anti-PD-1 and anti-CTLA-4 and anti-PD-1 monotherapy group, respectively. Among 314 patients receiving ICI first-line, PFS at 12 months was 33% in the anti-PD-1 group versus 38% in the combined anti-PD-1 and anti-CTLA-4 group (HR 0.8, 95% CI 0.6-1.0; p = 0.07). OS at 12 months was 54% in the anti-PD-1 group versus 66% in the combined ICI group (HR 0.7, 95% CI 0.5-1.0; p = 0.03). The ORR was 30% in the anti-PD-1 monotherapy group and 43% in the combined anti-PD-1 and anti-CTLA-4 group. Results from multivariate analysis confirmed the absence of qualitative confounding. CONCLUSIONS: Among BRAF-mutant patients with elevated LDH, combined anti-PD-1 and anti-CTLA-4 blockade seems to be associated with prolonged OS compared with first-line TT. Among patients receiving ICI as a first-line treatment, OS appears to be longer for the combination of anti-PD-1 and anti-CTLA-4 than for anti-PD-1 alone.

Clinical Management of Locally Advanced Basal-Cell Carcinomas and Future Therapeutic Directions.

Treatment of choice for nodular basal-cell carcinomas (BCCs) is complete excision, implying that small lesions are of minor concern. Metastasis is very rare (< 1%). However, locally advanced basal-cell carcinomas (laBCCs), which are ineligible for surgery or radiation, are a therapeutic challenge. First-generation Smoothened (SMO) inhibitors (vismodegib, sonidegib) have been approved for treatment, but common side effects limit their use. Numerous new compounds are being investigated in clinical trials as potential therapeutic alternatives, among them second-generation SMO inhibitors, other Hedgehog signaling pathway inhibitors, immune-checkpoint inhibitors and intralesional modalities such as oncolytic viruses. Neoadjuvant treatment regimens open another field. This article deals with the clinical management of laBCCs, based on the description of an illustrative case from our department featuring multiple extensive lesions of the scalp. In this short review we will discuss therapeutic options and implications for the future. Some of the new strategies might potentially evolve as alternatives in the management of genodermatoses such as basal-cell carcinoma syndrome, if proven effective and safe.

Talimogene Laherparepvec in Advanced Mucosal Melanoma of the Urethra Upon Primary Resistance on Immune Checkpoint Inhibition: A Case Report.

Background: Mucosal melanomas including melanomas of the urogenital tract represent a rare type of melanoma characterized by low mutational burden and poor prognosis. Immune checkpoint inhibition has so far only been assessed in a limited number of mucosal melanoma patients and, in contrast to response in cutaneous melanoma, was associated with disappointing response rates. The oncolytic viral immunotherapy Talimogene laherparepvec (T-VEC) has recently been approved for treatment of locally advanced or unresectable melanoma. T-VEC combines direct oncolytic effects with local and systemic immune-mediated anti-tumor response. Our rationale to use T-VEC in this case was an expected augmentation of immunogenicity by tumor lysis to overcome primary resistance of a mucosal melanoma to immune checkpoint blockade. Objective: To report the first case of an advanced mucosal melanoma of the urethra treated with intralesional application of Talimogene laherparepvec. Case Report: A 78-years old female patient was diagnosed with an advanced mucosal melanoma of the urethra with inguinal lymph node metastases and intravaginal mucosal metastases. Shortly after surgical resection of the tumor mass, intravaginal mucosal metastases, and new nodal metastases in proximity of the left iliac vessels were diagnosed. The patient was treated with the anti-PD1 antibody pembrolizumab and obtained a stable disease lasting for 30 weeks. However, upon checkpoint inhibition the patient developed a loco-regional progressive disease featuring bleeding intravaginal metastases, while nodal metastases remained stable. We stopped treatment with pembrolizumab and administered T-VEC directly into the intravaginal mucosal metastases. After five injections T-VEC yielded a partial response with clinical regression of the injected mucosal metastases. Disease remained stable for 16 weeks under biweekly T-VEC treatment. Thereafter the patient showed disease progression in nodal metastases. T-VEC was discontinued. Immunotherapy with pembrolizumab was restarted but failed to achieve a response. Finally, targeted therapy with imatinib was induced in presence of a druggable c-KIT mutation, leading to a considerable response of all tumor sites that is still ongoing. Conclusion: T-VEC represents an effective and well-tolerated treatment option for patients with loco-regionally advanced mucosal melanoma. In combination with immunotherapy, T-VEC bears the potential of synergistic effects to overcome the specific primary resistance of mucosal melanoma to immune checkpoint blockade.

Prognostic and predictive value of PD-L2 DNA methylation and mRNA expression in melanoma.

BACKGROUND: PD-L1 (programmed cell death 1 ligand 1) expression in melanoma has been associated with a better response to anti-PD-1 (programmed cell death 1) therapy. However, patients with PD-L1-negative melanomas can respond to anti-PD-1 blockade, suggesting that the other PD-1 ligand, PD-L2 (programmed cell death 1 ligand 2), might also be relevant for efficacy of PD-1 inhibition. We investigated PD-L2 expression and methylation as a prognostic and predictive biomarker in melanoma. METHODS: DNA methylation at five CpG loci and gene expression of PD-L2 were evaluated with regard to survival in 470 melanomas from The Cancer Genome Atlas. PD-L2 promoter methylation in correlation with PD-L2 mRNA and protein expression was analyzed in human melanoma cell lines. Prognostic and predictive value of PD-L2 methylation was validated using quantitative methylation-specific PCR in a multicenter cohort of 129 melanoma patients receiving anti-PD-1 therapy. mRNA sequencing data of 121 melanoma patients receiving anti-PD-1 therapy provided by Liu et al. were analyzed for PD-L2 mRNA expression. RESULTS: We found significant correlations between PD-L2 methylation and mRNA expression levels in melanoma tissues and cell lines. Interferon-γ inducible PD-L2 protein expression correlated with PD-L2 promoter methylation in melanoma cells. PD-L2 DNA promoter hypomethylation and high mRNA expression were found to be strong predictors of prolonged overall survival. In pre-treatment melanoma samples from patients receiving anti-PD-1 therapy, low PD-L2 DNA methylation and high PD-L2 mRNA expression predicted longer progression-free survival. CONCLUSION: PD-L2 expression seems to be regulated via DNA promoter methylation. PD-L2 DNA methylation and mRNA expression may predict progression-free survival in melanoma patients receiving anti-PD-1 immunotherapy. Assessment of PD-L2 should be included in further clinical trials with anti-PD-1 antibodies.