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We have reported that the IL-2 Luc assay can detect the effects of chemicals on IL-2 promoter activity by using a dual reporter cell line, 2H4 cells that measure IL-2 promoter-driven luciferase activity (IL2LA) and GAPDH promoter-driven luciferase activity (GAPLA). Since the IL-2 Luc assay cannot detect immunosuppressive drugs that are antimitotic towards rapidly proliferating cells, we attempted to establish a new assay to detect these chemicals by taking advantage of the dual reporter cell properties of 2H4 cells. We first determined the optimal incubation time with drugs and the seeding cell density, and confirmed that the change in GAPLA and IL2LA levels reflects the change in cell count and IL-2 production of 2H4 cells after drug treatment. We designed the IL-2 luciferase lymphotoxicity test (IL-2 Luc LTT) to detect the antimitotic effects of chemicals by modifying the protocol and criteria of the IL-2 Luc assay. To determine the performance of the IL-2 Luc LTT and that of the combination of the IL-2 Luc LTT and the IL-2 Luc assay, we examined 46 drugs: 19 immunosuppressive drugs with different mechanisms of action, 12 anti-cancer drugs, and 15 non-immunosuppressive drugs. The performances of the IL-2 Luc LTT, the IL-2 Luc assay and their combination were 43.3%, 61.3%, and 93.3%, respectively, for sensitivity, 84.6%, 53.3%, and 50.0%, respectively, for specificity, and 55.8%, 58.7%, and 79.5%, respectively, for accuracy. These results demonstrated that the combination of these two assays is promising for the detection of immunosuppressive drugs with different mechanisms of action.

The Toll-like receptor signaling pathway contributes to the regulation of intestinal homeostasis through interactions with commensal bacteria. Although the transcriptional regulator IκB-ζ can be induced by Toll-like receptor signaling, its role in intestinal homeostasis is still unclear. To investigate the role of IκB-ζ in gut homeostasis. DSS-administration induced colitis in control and IκB-ζ-deficient mice. The level of immunoglobulins in feces was detected by ELISA. The immunological population in lamina propria (LP) was analyzed by FACS. IκB-ζ-deficient mice showed severe inflammatory diseases with DSS administration in the gut. The level of IgM in the feces after DSS administration was less in IκB-ζ-deficient mice compared to control mice. Upon administration of DSS, IκB-ζ-deficient mice showed exaggerated intestinal inflammation (more IFN-g-producing CD4+ T cells in LP), and antibiotic treatment canceled this inflammatory phenotype. IκB-ζ plays a crucial role in maintaining homeostasis in the gut.

Systemic corticosteroid is indicated for vitiligo, especially for generalized and progressive vitiligo. However, no consensus exists yet for the dosages and modalities of systemic corticosteroid treatments for vitiligo. The purpose of this study is to validate the efficacy and safety of i.v. methylprednisolone pulse therapy (IVMP) for patients with progressive generalized vitiligo. We retrospectively reviewed the medical records of vitiligo patients treated in our institute for 10 years between January 2010 and December 2019. Among 525 vitiligo patients treated in 10 years, 33 vitiligo patients (aged, 8-78 years; 18 female and 15 males) received IVMP, a single course of daily 500 mg methylprednisolone application (8 mg/kg/day for children) for 3 consecutive days. We observed that 14 of 25 (56%) achieved stable condition without lesion progression, and 12 of 19 (63%) had more than 25% repigmentation at 6 months after IVMP. A group of Vitiligo Area Scoring Index over 10 included more patients with Vitiligo Disease Activity Score of +3 and +4 disease progression at 6 months after the IVMP. We did not observe any severe adverse events relating to the IVMP procedures. In conclusion, IVMP is a safe and effective treatment for progressive generalized vitiligo.

IL-1 functions as an essential pro-inflammatory mediator for the sensitisation of allergic contact dermatitis (ACD). However, studies conducted to date have typically used a limited number of haptens and examined their effects only on murine ACD or murine dendritic cells (DCs). It therefore remains unclear whether IL-1α and/or IL-1β is produced in ACD induced by haptens other than those commonly used in mouse ACD models, and whether they are essential for sensitisation leading to ACD in humans. In addition, it is unclear whether human DCs also produce IL-1α or IL-1β after stimulation by haptens in general. Here, we first demonstrated that 10 haptens (3 extreme, 1 strong, 3 moderate and 3 weak) increased both IL-1α mRNA and IL-1β mRNA expression by the human monocyte cell line THP-1, a commonly used surrogate of DCs in in vitro skin sensitisation tests. Next, we constructed an in vitro skin sensitisation test using a stable IL-1β reporter cell line, THP-G1b, and evaluated whether 88 haptens and 34 non-haptens increase IL-1β reporter activity. We found that 94% of 77 haptens evaluated after considering their applicability domain and solubility in the chosen media stimulated reporter activity. These studies demonstrated that most haptens, irrespective of their potency, increased IL-1β mRNA expression by THP-1 cells, confirming that human DCs also produce IL-1β after stimulation by most haptens. The luciferase assay using THP-G1b cells is thus another skin sensitisation test based on the adverse outcome pathway with reasonable performance.

The efficacy of encorafenib plus binimetinib (E + B) combination therapy for BRAF-mutated advanced melanoma as second-line therapy and beyond is still unknown. In this report, we investigated 22 cases of BRAF-mutated advanced melanoma treated with E + B combination therapy. The objective response rate (ORR) for the total cohort was 68.4%. Notably, the ORR for the second-line and beyond cohort was 73.3%, suggesting that the therapeutic effect of E + B combination therapy is comparable with that of first-line targeted therapy. In contrast, overall survival and progress-free survival in our present cohort was worse than that in a previous clinical trial. Notably, although the incidence rate of severe adverse events was higher than that in a previous report, our present study suggested that E + B combination therapy is a well-tolerated antimelanoma regimen. Our present study suggested that the efficacy and safety profile of E + B combination therapy as a second-line therapy and beyond is comparable with that of first-line targeted therapy.

Since the cost of molecular biological methods for Spitzoid neoplasms is expensive, the number of institutes that employ these methods might be limited. Preferentially expressed antigen in melanoma (PRAME) is a tumor-associated antigen that is useful to distinguish melanoma from other melanocytic disorders, including pediatric Spitzoid tumors that are difficult to diagnose by conventional methods alone. In this report, we report a case of PRAME-expressing juvenile Spitzoid melanoma with lymph node metastasis. Unexpectedly, there were few PRAME-expressing cells in the primary tumor, whereas most metastatic tumors expressed PRAME in the metastatic lymph node. These observations might suggest that, in Spitzoid melanomas, a limited number of melanoma cells possess metastatic potential and that metastatic lesions possess clonality.

A 66‐year‐old man with a 2‐year history of suspected scalp eczema with excessive dandruff developed painful swollen joints in the extremities. Four months after developing polyarthritis and polydactylitis, eczema gradually spread to the face. He was referred to our hospital for intractable scalp and facial eczema and polyarthritis. Based on the appearance of the head and facial skin lesions, psoriasis was suspected. Treatment with apremilast (a phosphodiesterase‐4‐inhibitor) was initiated, which swiftly alleviated the skin lesions. The joint deformities persisted, but the pain in the joints disappeared. This case implies that psoriatic arthritis should be suspected even if psoriatic skin lesions are localized to the scalp., Psoriatic arthritis was observed in a middle‐aged man with the skin lesions localized to scalp area. Because a delayed diagnosis may result in irreversible joint deformity, close collaboration with dermatologists is essential for early diagnosis of psoriatic arthritis in patients with localized skin lesions remote from the site of arthritis or dactylitis.

Stewart-Treves syndrome (STS) is a rare cutaneous lymphangiosarcoma developing from chronic lymph edema as a consequence of radical mastectomy or surgical invasion of the groin for the treatment of cervical or penile cancer. Previous reports suggested possible mechanisms in the development of lymphangiosarcoma that correlate with the immunological background of STS patients. In this report, we described two cases of STS developing in patients who underwent radical dissection for cervical cancer, we employed immunohistochemical staining of IL-23 and IL-17.

Immune checkpoint inhibitors (ICIs) significantly prolong survival in patients with metastatic melanoma but can lead to serious immune-related adverse events. In this report, we described a case of atypical neuropathy caused by nivolumab plus ipilimumab combination therapy before primary tumor resection. In our case, not only demyelinating neuropathy, but also muscle weakness and unilateral facial nerve palsy developed and manifested as severe and diverse symptoms. Moreover, unlike spontaneously developing demyelinating peripheral neuropathy, the present case suggested the therapeutic effects of high-dose methylprednisolone monotherapy for the treatment of ICIs-induced immune-related demyelinating peripheral neuropathy.

Bexarotene is useful for both early and advanced cutaneous T-cell lymphoma (CTCL), and is sometimes applied to ultraviolet-tolerant early CTCL patients as one of the first-line therapies in the real world. However, continuous administration of bexarotene is sometimes difficult because of its adverse events (AE). Development of an appropriate protocol for bexarotene that can induce a consistent response for CTCL without severe AE (SAE) is needed. We retrospectively investigated 29 Japanese cases of CTCL and evaluated the efficacy of treatment and incident ratios of all AE and SAE. Objective response rate (ORR) for the overall cohort was 65.5%. ORR of the 300 mg/m2 cohort (conventional dose) was 76.2%, while that of the 150-300 mg/body (low dose) with narrowband ultraviolet B light (NBUVB) cohort was 37.5%. Mean event-free survival was 10.0 months for all patients, 6.7 months for the bexarotene conventional-dose cohort and 19.1 months for the low-dose with NBUVB cohort. The incident ratio of total SAE for all patients was 20.7%. The incident ratio of total SAE was 23.8% for the conventional-dose cohort and 12.5% for the low-dose with NBUVB cohort. Our present study suggests that low-dose bexarotene plus NBUVB therapy is well-tolerated and could be one of the optimal therapies for advanced CTCL.

Since the incidence of mucosal melanoma is higher in the Japanese population compared to Caucasians, and since mucosal melanoma possesses a lower mutation burden compared to cutaneous melanoma, the efficacy of anti-PD1 antibody (Ab) monotherapy for mucosal melanoma is limited. Therefore, other targeting molecules that enhance the anti-tumor effects of immune checkpoint inhibitors are needed. In this report, we present a case with anti-PD1 Ab-resistant recurrent malignant melanoma of the nasal cavity successfully treated with nivolu­mab, ipilimumab plus denosumab combination therapy.

Enfortumab vedotin (EV) is a novel, fully humanized monoclonal antibody-drug conjugate composed of an anti-Nectin-4 antibody joined to monomethyl auristatin E. In this report, we described a case of a severe eczematoid and lichenoid eruption with full-thickness epidermal necrosis developing in patients with metastatic urothelial cancer treated with EV. Because phase II and phase III clinical studies are ongoing, in the future, substantial amounts of EV are expected to be used for the treatment of metastatic urothelial cancer. Therefore, understanding the mechanisms of drug eruption caused by EV is important for oncologists as well as dermatologists.

In our previous study, we successfully detected a difference in the effective thermal conductivity between an invasive melanoma lesion and healthy skin, through clinical experiments conducted on melanoma patients. We found that the effective thermal conductivity of the lesions correlated with the tumor thickness, suggesting that it may be correlated with the prognostic risk of melanoma. However, the bioheat transfer mechanisms of the correlation remained unknown. The aim of this study was to numerically investigate the effects of the bioheat transfer characteristics of malignant melanoma on thermal conductivity measurements and explore the cause of the difference in the effective thermal conductivity between lesions and healthy skin. We used two different bioheat transfer models, the Pennes model and local thermal nonequilibrium model, and investigated the cause of the aforementioned differences by varying the bioheat transfer parameters associated with the thermophysical properties and blood flow of a tumor. The calculation results indicated that the contribution of the blood flow can be dominant in a measurement comprising the use of a guard-heated thermistor probe. Therefore, we found that it is necessary to take into consideration the contribution of the convective term to the effective thermal conductivity of the lesion in order to explain the clinical data of a Stage IV invasive melanoma.

Patients with invasive extramammary Paget’s disease have an increased risk of secondary malignancy, mostly occurring colorectal carcinoma. TP53 is a regulator of apoptosis, cell cycle arrest, and DNA damage response pathways, and has been reported as one of the genetic biomarkers for colorectal carcinoma. In this report, we describe a case of advanced invasive EMPD concomitant with cecal cancer with a rare variant of TP53 single nucleotide polymorphism (rs121912665). To our knowledge, there is no English report that presents EMPD concomitant with cecal carcinoma.

Nivolumab plus ipilimumab combined therapy is one of the promising drugs that enhance the anti- immune response in patients with advanced melanoma. Therefore, to increase its response rate is of great interest to dermatologists. Recent reports suggested that, since CD8+ T cells after the administration of ICIs increase the RANKL expression to induce an immunosuppressive tumor microenvironment in melanoma, denosumab might enhance the anti-tumor effects of immune checkpoint inhibitors, such as nivolumab and ipilimumab. In this report, we present a case of multiple metastatic melanoma with nivolumab, ipilimumab plus denosumab combined therapy.

Anti-programmed death 1 antibody monotherapy is a first-line and widely used immunotherapy for the treatment of advanced melanoma. However, its efficacy rate is lower in the Japanese population compared with the Caucasian population. Ipilimumab is another immune checkpoint inhibitor (ICI) that activates and increases T cells, which suppress the function of regulatory T cells. Previous reports have suggested that ipilimumab is useful for treating advanced melanoma, particularly in combination with radiation therapy. In this report, we described three cases of nivolumab-resistant melanoma successfully controlled by ipilimumab with intensity-modulated radiotherapy, which may enhance the therapeutic effects of the sequential administration of ICI.

The mechanisms underlying itch are not fully understood. Physicians usually encounter difficulty controlling itch in generalized pruritus. Since only a small percentage of patients with generalized pruritus respond to antihistamines (H1 receptor antagonists), a variety of itch mediators and mechanisms other than histaminergic signals are considered to be involved in itch for these non-responsive patients. In 2012, we created guidelines for generalized pruritus. Those guidelines have been updated and revised to make some of the definitions, diagnostic terms, and classifications more applicable to daily clinical practice. Cutaneous pruritus as designated in these guidelines is a disease characterized by itch without an observable rash. Generalized pruritus (without skin inflammation) is defined as the presence of itch over a wide area, and not localized to a specific part of the body. This entity includes idiopathic pruritus, pruritus in the elderly, symptomatic pruritus, pregnancy-associated pruritus, drug-induced pruritus, and psychogenic pruritus. Localized pruritus (without skin inflammation) represents fixed itch localized to a specific part of the body, and includes anogenital pruritus, scalp pruritus, notalgia paresthetica, and brachioradial pruritus. These guidelines outline the current concepts and specify the diagnostic methods/treatments for cutaneous pruritus.

Alopecia areata (AA) is a chronic autoimmune skin disease with hair loss, which often results in a poor prognosis. Although the high-dose intravenous methylprednisolone pulse therapy (IVMP) is used for AA, predictive factors affecting efficacies of IVMP are not fully elucidated. Thus, we conducted a retrospective study reviewing IVMP for AA during January 2009 and December 2018. The study was approved by the ethical committee of the Tohoku University Graduate School of Medicine.

Prurigo is a treatment-resistant skin disease characterized by multiple isolated papules/nodules that cause severe itch. Prurigo papules/nodules occur either as primary lesions or as secondary lesions due to persistent scratching. The fundamental concepts and classifications of prurigo have not been sufficiently established, and considerable confusion remains regarding this topic. Clinical guidelines for chronic prurigo in Japan were published in 2012 in an attempt to reduce confusion regarding the concepts of prurigo and to standardize laboratory tests and treatments. However, the diagnostic terms for prurigo and associated concepts have changed over time, and new forms of treatment are under development. We have, thus, updated and revised the guidelines to classify prurigo based on clinical forms and causes, and disease name classifications based on the clinical form have been further simplified, such as prurigo nodularis, prurigo chronica multiformis, and prurigo (not otherwise specified). Expressions for acute, subacute, and chronic forms are not used. These guidelines outline the current concepts and specify treatments for prurigo.

Biologics has had a great impact on psoriasis treatment as well as the life of psoriasis patients. Infliximab (IFX), one of the biologics targeting tumor necrosis factor (TNF), is the first of the biologics introduced to Japanese psoriasis patients. Many patients had benefits of IFX from initial applications and sustained remission of skin lesions and arthritis. Some, however, fall into so-called secondary failure, in which patients become less responsive to IFX when the treatment is repeated. The mechanism of secondary failure and the background of patients with secondary failure have not been completely elucidated. To address this issue, we retrospectively evaluated psoriasis patients treated with IFX in our department. In this retrospective, single-center, case-control study based on the clinical record, a total of 34 patients were enrolled. We excluded 7 patients who discontinued IFX because of adverse events of IFX. We divided other 27 patients into two groups; 16 patients who kept using IFX (Continuance group); and 11 patients who switched to other treatments (Discontinuance group). Among various clinical features, body mass index (BMI), HbA1c, and serum CRP level were significantly higher in the Discontinuance group than the Continuance group. The results indicated that these three clinical features of BMI, HbA1c and serum CRP level before treatment are the predictors of successful IFX treatment and suggest that improvement of metabolic conditions contributes to avoiding secondary failure and discontinuance of IFX.

BRAF kinase inhibitors in combination with MEK kinase inhibitors are among the most promising chemotherapeutic regimens for the treatment of advanced BRAF-mutant melanoma. Although the NCCN guideline for cutaneous melanoma recommended BRAF/MEK inhibitors as first-line therapies for unresectable BRAF-mutated melanoma, resistance to these drugs should be taken into account in real-world practice. Therefore, development of a protocol for BRAF/MEK inhibitor-resistant advanced melanoma is needed. In this report, a case of BRAF/MEK inhibitor-resistant advanced cutaneous melanoma that was successfully treated with nivolumab plus ipilimumab combination therapy followed by intensity-modulated radiotherapy (IMRT) is reported. In the present case, not only the locally irradiated lesion, but remote metastases including inguinal lymph nodes decreased after ipilimumab plus nivolumab followed by IMRT treatment leading to complete remission, suggesting that IMRT triggered an abscopal response. Moreover, immunohistochemical analysis showed increased CD3+ , CD4+ , and CD8+ T cells after radio-immunotherapy (RIT). This case suggests that RIT might break the tolerance in the tumor microenvironment and induce a systemic anti-melanoma immune response.

Genome-wide association studies have identified more than 60 susceptibility loci for psoriasis, highlighting the role of genetics in psoriasis development. Although the HLA region is suggested as the most prominent susceptibility locus, the role of the HLA haplotype in the development of psoriasis is unclear. The aim of this study is to investigate how HLA haplotype changes affect the onset of psoriasis and which HLA haplotypes are associated with the development of psoriasis. A longitudinal, retrospective case series study of children was conducted at Tohoku University Hospital in Japan, between November 1981 and October 2020. We evaluated a total of 378 pediatric patients who underwent hematopoietic stem cell transplantation in the Department of Pediatrics. The background of these patients and their HLA haplotypes before and after transplantation was assessed. Among the 378 cases, aged 0-22 years old (median age 6) identified, 117 cases received autologous transplantation, 260 cases received allogeneic transplantation, and one case received syngeneic transplantation. Only two cases developed de novo psoriasis, and these cases had acquired HLA-B46-Cw1 after allogeneic transplantation. Others who had HLA-B46-Cw1 before and after allogeneic transplantation did not develop psoriasis. Our findings suggest that the HLA-B46 and HLA-Cw1 combination contributes to the development of psoriasis in this Asian population.

Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine carcinoma that tends to show local recurrence and metastasis. Typically, MCC is polyomavirus (MCPyV)-associated and cytokeratin 20 (CK20) positive. However, little is known about this tumor and its origins. Here, we aimed to determine the developmental origins of MCC and to identify prognostic clinicopathologic factors. Initial examinations revealed that CK20 and MCPyV expression (CK20+, MCPyV+ (60%); CK20+, MCPyV- (10%); CK20-, and MCPyV- (30%)) did not affect overall survival. With RB1 gene sequencing of FFPE specimens, which covered an entire exon, all RB1 mutation-positive cases showed positive regional lymph node and/or distant metastases (8/8 cases, 100%), whereas the frequency of the metastasis was statistically significantly lower in RB1 mutation-negative cases, (10/16 cases, 62%, P = 0.033). The results were also confirmed with immunohistochemistry, and either RB1 alterations, entire exon sequencing, or immunohistochemistry was associated with the metastasis (P = 0.007). RB1 alterations may be used to access the aggressive clinical course of MCC.

The most common adverse event of epidermal growth factor receptor inhibitors, used to treat colorectal, non-small cell lung, and head and neck cancers, is acneiform eruption, with a profound effect on treatment continuation. Prolonged acneiform eruptions treated with topical corticosteroids, a standard management, may be associated with secondary bacterial infections, thus there is a need for new treatments. We conducted a multicenter, phase II trial to evaluate the efficacy and safety of topical benzoyl peroxide for epidermal growth factor receptor inhibitor-induced prolonged acneiform eruptions. Patients with colorectal, non-small lung cell, and head and neck cancers who received epidermal growth factor receptor inhibitors for >10 weeks and had persistent acneiform eruptions were eligible. Topical benzoyl peroxide was applied to the affected area of the face once daily for 8 weeks; a clinical evaluation was performed every 2 weeks. The primary endpoint was a change in acneiform eruption severity evaluated between disease onset and end of the treatment period. The quality of life of patients was assessed using the Dermatology Life Quality Index. Of the 14 enrolled patients, 11 completed the trial. The protocol-specified grade of acneiform eruptions from baseline to week 8 improved from 2.0 to 1.0 (P < 0.01). The dermatology life quality index score from baseline to week 8 improved from 3.0 to 1.0 point (P < 0.01). No patient experienced severe adverse events. Overall, topical benzoyl peroxide may be effective for treating and managing prolonged acneiform eruptions induced by epidermal growth factor receptor inhibitors.

Although various anti-cutaneous T-cell lymphoma (CTCL) therapies are available for clinical use, appropriate chemotherapy lines for the treatment of CTCLs have yet to be established. Therefore, to date, various clinical trials for the treatment of advanced CTCLs are ongoing. In this review, we evaluate the therapeutic options that are available in clinical practice for treatment of early- and advanced-stage CTCLs (targeted therapies, histone deacetylase (HDAC) inhibitors, retinoids, interferons, cytotoxic drugs, etc.). We also examine clinical trials of novel regimens for the treatment of CTCLs.

Skin pigmentation is associated with skin damages and skin cancers, and ultraviolet (UV) photography is used as a minimally invasive mean for the assessment of pigmentation. Since UV photography equipment is not usually available in general practice, technologies emphasizing pigmentation in color photo images are desired for daily care. We propose a new method using conditional generative adversarial networks, named UV-photo Net, to generate synthetic UV images from color photo images. Evaluations using color and UV photo image pairs taken by a UV photography system demonstrated that pigment spots were well reproduced in synthetic UV images by UV-photo Net, and some of the reproduced pigment spots were difficult to be recognized in color photo images. In the pigment spot detection analysis, the rate of pigment spot areas in cheek regions for synthetic UV images was highly correlated with the rate for UV photo images (Pearson’s correlation coefficient 0.92). We also demonstrated that UV-photo Net was effective for floating up pigment spots for photo images taken by a smartphone camera. UV-photo Net enables an easy assessment of pigmentation from color photo images and will promote self-care of skin damages and early signs of skin cancers for preventive medicine.

Various adverse events (AEs) have been reported to occur at a high rate in patients treated with dabrafenib plus trametinib (D + T) combination therapy. Among such AEs, the incidence of pyrexia was highest among the series of AEs in patients treated with D + T combination therapy. Although little is known about the mechanisms of pyrexia caused by D + T combination therapy, a recent report suggested that sCD163, as well as interferon-inducible chemokines (CXCL9, CXCL10, CXCL11), might correlate with pyrexia caused by encorafenib plus binimetinib combination therapy. In addition to these soluble factors, CXCL5 is a biomarker for predicting immune-related AEs in melanoma patients treated with nivolumab. From the above findings, we hypothesized that these soluble factors might also correlate with the onset of AEs in D + T combination therapy. The serum levels of sCD163 were increased in patients with pyrexia in parallel with their severity, whereas the serum levels of CXCL5 were increased in patients without pyrexia. Moreover, increased levels of CXCL9, CXCL10, and CXCL11 were prominent in patients with AEs over G2 levels. As these chemokines recruit Th1, Th17, and activated CD8+ T cells, increased serum levels of these chemokines might correlate with the positive feedback of inflammatory reactions related to AEs.

Therapeutic options for treating advanced melanoma are progressing rapidly. Until six years ago, the regimen for treating advanced melanoma mainly comprised cytotoxic agents such as dacarbazine, and type I interferons. Since 2014, anti-programmed cell death 1 (PD1) antibodies have become recognized as anchor drugs for treating advanced melanoma with or without additional combination drugs such as ipilimumab. In addition, v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) kinase inhibitors in combination with mitogen-activated protein kinase kinase (MEK) inhibitors are among the most promising chemotherapeutic regimens for treating advanced BRAF-mutant melanoma, especially in patients with low tumor burden. Since anti-PD1 antibodies are widely applicable for the treatment of both BRAF wild-type and mutated advanced melanomas, several clinical trials for drugs in combination with anti-PD1 antibodies are ongoing. This review focuses on the development of the anti-melanoma therapies available today, and discusses the clinical trials of novel regimens for the treatment of advanced melanoma.

Mogamulizumab is a humanized anti-C-C chemokine receptor type (CCR)4 antibody that shows cytotoxicity against CCR4+ lymphoma cells via antibody-dependent cell-mediated cytotoxicity in advanced cutaneous T cell lymphoma (CTCL) patients. The production levels of ligands for CCR4, that is, Chemokine (C-C motif) ligand (CCL)17 and CCL22, are important for the assessment of the disease activity in CTCL patients. We evaluated the serum levels of CCL17, CCL19, CCL22, C-X-C motif chemokine ligand (CXCL)10, and CXCL13, which are ligands for CCR4, CCR7, CCR4, C-X-C Motif Chemokine Receptor (CXCR)3, and CXCR5, respectively, at baseline and 4 weeks after the administration of mogamulizumab in five patients with mycosis fungoides. The serum levels of CCL22 were significantly decreased in patients who responded to mogamulizumab, but no differences were identified in the serum levels of CCL17, CCL19, CXCL10, or CXCL13. Immunofluorescence staining revealed that the majority of CCL22-producing cells were cluster of differentiation (CD)163+ tumor-associated macrophages, and they were surrounded by CCR4+ CTCL cells. Our present data suggested that the serum CCL22 level may be a predictive marker of the efficacy of mogamulizumab for the treatment of CCR4+ CTCL.

Costello syndrome is an autosomal dominant disorder that is caused by germline HRAS mutations. Patients with Costello syndrome present craniofacial abnormalities, cardiac defects, and cancer predisposition, as well as skin abnormalities, including papillomas, keratosis pilaris, and eczematous dermatitis. However, the mechanisms underlying the dermatological abnormalities remain unclear. Here, we demonstrated that knock-in mice expressing an Hras G12S mutation (HrasG12S/+ mice) are susceptible to develop atopic dermatitis (AD)-like skin lesions, including eczema, pruritus, elevated serum IgE levels, acanthosis, and the infiltration of mast cells, basophils, and type-2 innate lymphoid cells in the dermis, after stimulation with house dust mite allergens (Dermatophagoides farinae, Dfb). Reduced skin barrier function, increased proliferation of phosphorylated ERK (p-ERK)-positive epidermal cells, and increased Th2-type cytokines as well as epithelial cell-derived cytokines, including IL-33, were observed in the skin tissue of HrasG12S/+ mice compared with Hras+/+ mice. Cultured HrasG12S/+ keratinocytes exhibited increased IL-33 expression after Dfb stimulation. PD0325901, an MEK inhibitor, ameliorated AD-like symptoms in HrasG12S/+ mice, showing decreased proliferation of p-ERK-positive epidermal cells and decreased expression of IL-33. Our findings indicate that the epidermis of HrasG12S/+ mice stimulated by Dfb strongly induced IL-33 expression and type-2 innate lymphoid cells, resulting in AD-like skin lesions. These results suggest that the epidermis of HrasG12S/+ mice are prone to development of eczematous dermatitis stimulated with house dust mite allergens.

Nivolumab plus ipilimumab combined therapy is among the most effective therapies for advanced melanoma. However, this therapy is also associated with a high frequency of immune-related adverse events (irAEs). To avoid such severe irAEs caused by additional administration of anti-CTLA4 antibodies, biomarkers to distinguish responders from non-responders among patients treated with anti-PD1 antibodies are important. The purpose of this study is to evaluate the increased serum levels of CCL11, CCL24, and CCL26 as a predictive biomarker for the efficacy of anti-PD1 antibodies in advanced cutaneous melanoma patients. This study analyzed increased serum levels of CCL11, CCL24, and CCL26 in 46 cases of advanced cutaneous melanoma treated with anti-PD1 antibodies. Serum levels on day 42 were compared to baseline (day 0) and analyzed statistically. Receiver operating characteristic curves were established to evaluate the correlation between serum levels of CCL11, CCL24, and CCL26 and efficacy of anti-PD1 antibodies. Increased serum levels of CCL26 correlated significantly with the efficacy of anti-PD1 antibodies. In contrast, no significant correlations were seen between increased serum levels of CCL11 and CCL24 and efficacy of anti-PD1 antibodies. Increased serum levels of CCL26 may be a useful biomarker for identifying those patients with advanced cutaneous melanoma most likely to benefit from anti-melanoma immunotherapy.

Tumor-associated macrophages (TAMs) have been detected in most skin cancers. TAMs produce various chemokines and angiogenic factors that promote tumor development, along with other immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) and tumor-associated neutrophils. TAMs generated from monocytes develop into functional, fully activated macrophages, and TAMs obtain various immunosuppressive functions to maintain the tumor microenvironment. Since TAMs express PD1 to maintain the immunosuppressive M2 phenotype by PD1/PD-L1 signaling from tumor cells, and the blockade of PD1/PD-L1 signaling by anti-PD1 antibodies (Abs) activate and re-polarize TAMs into immunoreactive M1 phenotypes, TAMs represent a potential target for anti-PD1 Abs. The main population of TAMs comprises CD163+ M2 macrophages, and CD163+ TAMs release soluble (s)CD163 and several proinflammatory chemokines (CXCL5, CXCL10, CCL19, etc.) as a result of TAM activation to induce an immunosuppressive tumor microenvironment together with other immunosuppressive cells. Since direct blockade of PD1/PD-L1 signaling between tumor cells and tumor-infiltrating T cells (both effector T cells and Tregs) is mandatory for inducing an anti-immune response by anti-PD1 Abs, anti-PD1 Abs need to reach the tumor microenvironment to induce anti-immune responses in the tumor-bearing host. Taken together, TAM-related factors could offer a biomarker for anti-PD1 Ab-based immunotherapy. Understanding the crosstalk between TAMs and immunosuppressive cells is important for optimizing PD1 Ab-based immunotherapy.

Although the number of cutaneous squamous cell carcinoma (cSCC) cases is increasing, the effectiveness of systemic therapy for the treatment of advanced cSCC is limited. Since cSCC possesses a high tumor mutation burden (TMB) compared to other cancer species, and since high TMB correlated with increased neoantigens and the efficacy of anti-PD1 antibodies (Abs) in various cancers, cSCC could be a target for anti-PD1 Abs monotherapy. In this report, we describe a case of unresectable recurrent cSCC of the scalp with meningeal invasion, but highly expressed programmed death-ligand 1 (PD-L1), treated with nivolumab monotherapy.