Pseudotumor of the skin due to Mycobacterium genavense.

Mycobacterium genavense is a rare type of nontuberculous Mycobacterium that has been reported to cause disseminated infections in patients who are immunocompromised. Because M. genavense is slow-growing and poorly able to form colonies on Ogawa medium, genetic and molecular analyses are necessary to identify this pathogen. Nontuberculous Mycobacterium infections present with various cutaneous manifestations. Of these, rare cases have been reported to present with mycobacterial pseudotumors. However, there are no reports of M. genavense with cutaneous pseudotumors. In this paper, we report a case of a pseudotumor due to M. genavense infection that was observed only in a cutaneous lesion. The patient was taking 5 mg of prednisolone and was aware of a tumor on the right lower leg. Biopsy samples showed diffuse spindle-shaped histiocytes and various other inflammatory cell infiltrates, and Ziehl-Neelsen staining detected Mycobacterium. Because no colonies formed on the Ogawa medium, genetic testing was performed, and M. genavense was identified by DNA sequence analysis. There were no other disseminated lesions beyond the skin, including in the lungs and liver. Because the patient was immunosuppressed, in accordance with previous literature, a combination therapy of clarithromycin, ethambutol, and rifampicin for 4 months was recommended. When no growth is observed on the Ogawa medium in cases of infection, it is essential to identify the infectious pathogen by genetic analysis.

Zonula occludens-1 distribution and barrier functions are affected by epithelial proliferation and turnover rates.

Zonula occludens-1 (ZO-1) is a scaffolding protein of tight junctions, which seal adjacent epithelial cells, that is also expressed in adherens junctions. The distribution pattern of ZO-1 differs among stratified squamous epithelia, including that between skin and oral buccal mucosa. However, the causes for this difference, and the mechanisms underlying ZO-1 spatial regulation, have yet to be elucidated. In this study, we showed that epithelial turnover and proliferation are associated with ZO-1 distribution in squamous epithelia. We tried to verify the regulation of ZO-1 by comparing normal skin and psoriasis, known as inflammatory skin disease with rapid turnover. We as well compared buccal mucosa and oral lichen planus, known as an inflammatory oral disease with a longer turnover interval. The imiquimod (IMQ) mouse model, often used as a psoriasis model, can promote cell proliferation. On the contrary, we peritoneally injected mice mitomycin C, which reduces cell proliferation. We examined whether IMQ and mitomycin C cause changes in the distribution and appearance of ZO-1. Human samples and mouse pharmacological models revealed that slower epithelial turnover/proliferation led to the confinement of ZO-1 to the uppermost part of squamous epithelia. In contrast, ZO-1 was widely distributed under conditions of faster cell turnover/proliferation. Cell culture experiments and mathematical modelling corroborated these ZO-1 distribution patterns. These findings demonstrate that ZO-1 distribution is affected by epithelial cell dynamics.

Zonula occludens-1 demonstrates a unique appearance in buccal mucosa over several layers.

Tight junctions (TJs) firmly seal epithelial cells and are key players in the epithelial barrier. TJs consist of several proteins, including those of the transmembrane claudin family and the scaffold zonula occludens (ZO) family. Epithelial tissues are exposed to different conditions: to air in the stratified epithelium of the skin and to liquids in the monolayer of the intestine. The TJs in stratified oral mucosal epithelium have remained insufficiently elucidated in terms of distributions, appearances and barrier functions of TJ proteins in normal buccal mucosa. We investigated these and ZO-1 and claudin-1 were found to be expressed in the top third and in the bottom three quarters of the mucosal epithelium. ZO-1 in the buccal mucosa was found to have an irregular linear appearance. ZO-1 in the buccal mucosa continuously existed in several layers. Electron microscopy revealed the buccal mucosa to have kissing points. In a biotin permeation assay that sought to investigate inside-outside barrier function, the biotin tracer penetrated several ZO-1 layers but did not pass through all the ZO-1 layers. We found that the oral mucosal cell knockdown of TJP1 or CLDN1 resulted in decreases of TER but no significant change in FITC-dextran leakage. Our results suggest that the distribution and appearance of ZO-1 in the buccal mucosa differ from those in the skin. We were unable to prove barrier function in this study but we did show barrier function against small molecules in vivo and against ions in vitro.

Loss of dynamin-related protein 1 (Drp1) does not affect epidermal development or UVB-induced apoptosis but does accelerate UVB-induced carcinogenesis.

BACKGROUND: Mitochondrial morphology is controlled by fission and fusion. Dynamin-related protein 1 (Drp1, dynamin-1-like protein (Dnml1)) regulates mitochondrial fission, which is associated with cell division and apoptosis. We previously reported that DRP1 is indispensable for cell growth in cutaneous squamous cell carcinoma. However, little is known about Drp1 in normal epidermis/keratinocytes. OBJECTIVES: We investigated the function of Drp1 in normal epidermis/keratinocytes. METHODS: Epidermis-specific Drp1 knockout (EKO) mice were analyzed. RESULTS: Epidermal development in the EKO mice were indistinguishable from those in the wild-type (WT) mice. Ultrastructural analysis and immunohistochemistry revealed that the mitochondria of keratinocytes in the EKO mice were neither elongated nor constricted. Drp1 knockdown did not diminish the cell growth of normal human keratinocytes. Both in vivo and in vitro, UVB-induced apoptosis in the EKO epidermis and keratinocytes did not differ from that in the WT mice. In chronic UVB-irradiation, the loss of Drp1 sensitized the epidermis to the development of skin tumors. Clinically, DRP1 is expressed more highly in sun-exposed skin than in non-exposed skin in individuals under age 40, but not in those over age 60. CONCLUSION: EKO mice demonstrate that Drp1 is dispensable for the development and apoptosis of the epidermis. Drp1 plays critical roles in malignant tumors; thus, the molecular machinery of mitochondrial dynamics involving Drp1 could be a novel therapeutic target for malignant keratinocytic lesions. On the other hand, the anti-tumorigenic role of Drp1 in chronic UVB-induced carcinogenesis need to be further investigated.

Japanese Dermatological Association Guidelines: Outlines of guidelines for cutaneous melanoma 2019.

With consideration of the ongoing developments in treatment options for cutaneous melanoma, the Japanese Skin Cancer Society published the first guidelines for cutaneous melanoma in 2007 and later revised them in 2015. Here, we report on an English version of the 2019 Japanese Melanoma Guidelines. In this latest edition, all processes were carried out according to the Grading of Recommendations, Assessment, Development and Evaluation system. A comprehensive published work search, systematic review and determination of recommendations in each clinical question were performed by a multidisciplinary expert panel consisting of dermatologists, a plastic and reconstructive surgeon, and a radiation oncologist. The advent of novel agents, such as immune checkpoint inhibitors and molecular-targeted agents, has drastically changed the nature of treatment for adjuvant and advanced-stage diseases among melanoma patients worldwide. Additionally, recent reports of clinical trials regarding surgical procedures and a better understanding of molecular biology and tumor immunology in clinical types of melanoma have had an impact on clinical practise. Based on these viewpoints, eight relevant clinical questions were raised in this report that aim to help clinicians select the appropriate therapeutic approach.

Serum Level of Soluble CD163 May Be a Predictive Marker of the Effectiveness of Nivolumab in Patients With Advanced Cutaneous Melanoma.

Antibodies against programmed cell death protein 1, such as nivolumab and pembrolizumab, are widely used for treating various cancers, including advanced melanoma. Nivolumab significantly prolongs survival in patients with metastatic melanoma, and sequential administration with lipilimumab may improve outcomes when switched at the appropriate time. Biomarkers are therefore needed to evaluate nivolumab efficacy soon after first administration. This study analyzed serum levels of soluble cluster of differentiation 163 (sCD163) in 59 cases of advanced cutaneous melanoma and 16 cases of advanced mucosal melanoma treated using nivolumab. Serum levels of sCD163 were significantly increased after 6 weeks in responders compared to non-responders after initial administration of nivolumab for cutaneous melanoma. In contrast, no significant difference between responders and non-responders was seen among patients with non-cutaneous melanoma. These results suggest that sCD163 may be useful as a biomarker for selecting patients with advanced cutaneous melanoma most likely to benefit from anti-melanoma immunotherapy.

Loss of TRIM29 Alters Keratin Distribution to Promote Cell Invasion in Squamous Cell Carcinoma.

: TRIM29 (tripartite motif-containing protein 29) is a TRIM family protein that has been implicated in breast, colorectal, and pancreatic cancers. However, its role in stratified squamous epithelial cells and tumors has not been elucidated. Here, we investigate the expression of TRIM29 in cutaneous head and neck squamous cell carcinomas (SCC) and its functions in the tumorigenesis of such cancers. TRIM29 expression was lower in malignant SCC lesions than in adjacent normal epithelial tissue or benign tumors. Lower expression of TRIM29 was associated with higher SCC invasiveness. Primary tumors of cutaneous SCC showed aberrant hypermethylation of TRIM29. Depletion of TRIM29 increased cancer cell migration and invasion; conversely, overexpression of TRIM29 suppressed these. Comprehensive proteomics and immunoprecipitation analyses identified keratins and keratin-interacting protein FAM83H as TRIM29 interactors. Knockdown of TRIM29 led to ectopic keratin localization of keratinocytes. In primary tumors, lower TRIM29 expression correlated with the altered expression of keratins. Our findings reveal an unexpected role for TRIM29 in regulating the distribution of keratins, as well as in the migration and invasion of SCC. They also suggest that the TRIM29-keratin axis could serve as a diagnostic and prognostic marker in stratified epithelial tumors and may provide a target for SCC therapeutics. SIGNIFICANCE: These findings identify TRIM29 as a novel diagnostic and prognostic marker in stratified epithelial tissues.

Serum levels of soluble CD163 and CXCL5 may be predictive markers for immune-related adverse events in patients with advanced melanoma treated with nivolumab: a pilot study.

Antibodies against PD-1, such as nivolumab and pembrolizumab, are widely used in the treatment of various cancers including advanced melanoma. The anti-PD-1 Ab significantly prolongs survival in patients with metastatic melanoma, and its administration in combination with local or systemic therapy may also lead to improved outcomes. Although anti-PD-1 Ab-based combined therapy might be effective for the treatment of advanced melanoma, the associated risk of irAEs is an important consideration. Therefore, being able to predict irAEs is of great interest to oncologists. The purpose of this study was to evaluate the value of using serum levels of sCD163 and CXCL5 to predict irAEs in patients with advanced melanoma who were administered nivolumab. To this end, we analyzed these serum levels in 46 cases of advanced melanoma treated with nivolumab. In addition, the tumor stroma was evaluated by immunohistochemistry and immunofluorescence. We measured the serum levels of sCD163 and CXCL5 on day 0 (immediately before nivolumab administration) and day 42. The serum absolute levels of sCD163 were significantly increased in patients who developed AEs (p = 0.0018). Although there was no significant difference in serum levels of CXCL5, the absolute value of CXCL5 could at least be a supportive marker for the increased absolute levels of serum sCD163. This study suggests that sCD163 and CXCL5 may serve as possible prognostic biomarkers for irAEs in patients with advanced melanoma treated with nivolumab.

Enhanced IL-34 expression in Nivolumab-resistant metastatic melanoma.

BACKGROUND: Immunotherapies that target immune-checkpoint molecules such PD-1 have helped to achieve durable responses in melanoma treatment. However, 25% of melanoma patients who showed objective responses to PD-1 blockade develop resistance and suffer from disease progression and ultimately death, which necessitates the identification of related resistance mechanisms.IL-34 is a cytokine that controls the biology of myeloid cell lineage through binding to CSF-1R. IL-34 is importantly involved in the pathogenesis of various diseases. In cancer, the expression of IL-34 has been suggested to associate with tumor growth, metastasis, angiogenesis, and therapeutic resistance such as in lung cancers and malignant pleural mesotheliomas. In this study, we evaluate the possible involvement of IL-34 in immunotherapeutic resistance. CASE PRESENTATION: Melanoma resection species were obtained from a patient who developed a refractory melanoma against immunotherapy with Nivolumab, and stained with anti-IL-34, anti-melanoma antigens and anti-CD163 antibody. Staining of these markers was compared between primary or metastatic refractory melanoma tissues. Immunohistochemistry staining of melanoma tissues showed an enhanced expression of IL-34 in metastatic refractory melanoma compared to primary melanoma tissues, which correlates with increased frequencies of CD163+ macrophages. CONCLUSION: We introduce for the first time a clinical case of a patient with metastatic refractory melanoma that acquired resistance to anti-PD-1 immunotherapy, showing an enhanced expression of IL-34 in refractory melanoma tissues.

Retrospective study of advanced melanoma patients treated with ipilimumab after nivolumab: Analysis of 60 Japanese patients.

BACKGROUND: Due to resistance and immune-related adverse events (irAE) some melanoma patients require ipilimumab after nivolumab therapy. However, little is known about the result of this switching. OBJECTIVE: Investigate the outcome of ipilimumab switching in Japanese patients. METHODS: We retrospectively collected 60 patients who were treated with ipilimumab after nivolumab from 9 institutes in Japan. Information of the primary tumor, treatment, response, irAE), and survival was collected. RESULTS: In our cohort, acral lentiginous and mucosal melanoma accounted for 53% of the cases. The most common reason for initiating ipilimumab was disease progression (93%). Median interval from the last nivolumab administration to first ipilimumab administration was 29days. Only 38% of patients completed 4 injections of ipilimumab. The best overall response was 3.6%. IrAE occurred in 78% of patients and 70% of those were of grade 3/4 (G3/4) and 31% of patients experienced 2 or more irAEs. An within interval of 28days or less between the last nivolumab administration and ipilimumab administration was correlated with the development of G3/4 pyrexia and 3 or more irAEs, but irAE occurrence did not affect survival. Multivariate analysis showed that endocrine irAE (relative risk=0.22, P=0.015) and skin irAE (relative risk=2.78, P=0.048) were significant factors associated with survival. CONCLUSION: In our study, the response ratio to ipilimumab after nivolumab was unsatisfactory and associated with a high frequency of severe irAEs. As there are few second-line treatment options for patients with BRAF wild-type advanced melanoma after nivolumab failure, patients should be closely monitored if ipilimumab is initiated.

Lipofuscin deposition causes the pigmentation of apocrine hidrocystoma.

Apocrine hidrocystoma (AHC) is a benign cystic lesion arising from apocrine glands and frequently presents as a blue hae with a whitish gloss. It has been reported that the amount of lipofuscin and the degree of its oxidation determines the pigmentation of AHC. However, little is known about the correlation between clinical color and lipofuscin granules. In this study, we histopathologically investigated three cases of AHC and statistically analyzed the quantitative correlation between the clinical color tone and the amount of cytoplasmic lipofuscin deposits. The color tone was quantified as the mean gray value using Image J software. Statistical analysis showed a negative correlative tendency (P = 0.09) between the color tone and the amount of lipofuscin. Our study suggests that the color tone of AHC is associated with the amount of lipofuscin.