Impact of protein and small molecule interactions on kinase conformations.

Protein kinases act as central molecular switches in the control of cellular functions. Alterations in the regulation and function of protein kinases may provoke diseases including cancer. In this study we investigate the conformational states of such disease-associated kinases using the high sensitivity of the kinase conformation (KinCon) reporter system. We first track BRAF kinase activity conformational changes upon melanoma drug binding. Second, we also use the KinCon reporter technology to examine the impact of regulatory protein interactions on LKB1 kinase tumor suppressor functions. Third, we explore the conformational dynamics of RIP kinases in response to TNF pathway activation and small molecule interactions. Finally, we show that CDK4/6 interactions with regulatory proteins alter conformations which remain unaffected in the presence of clinically applied inhibitors. Apart from its predictive value, the KinCon technology helps to identify cellular factors that impact drug efficacies. The understanding of the structural dynamics of full-length protein kinases when interacting with small molecule inhibitors or regulatory proteins is crucial for designing more effective therapeutic strategies.

Prophylactic IL-23 blockade uncouples efficacy and toxicity in dual CTLA-4 and PD-1 immunotherapy.

BACKGROUND: Immune-related adverse events (irAEs), characterized by targeted inflammation, occur in up to 60% of patients with melanoma treated with immune checkpoint inhibitors (ICIs). Evidence proved that the baseline peripheral blood profiles of patients at risk for severe irAEs development paralleled clinical autoimmunity. Interleukin (IL)-23 blockade with risankizumab is recommended for cases that are suffering from autoimmune disease, such as autoimmune colitis. However, currently, the role of IL-23 in irAEs onset and severity remains poorly understood. METHODS: The pro-inflammatory cytokines most associated with severe irAEs onset were identified by retrospective analysis based on GSE186143 data set. To investigate the efficacy of prophylactic IL-23 blockade administration to prevent irAEs, refer to a previous study, we constructed two irAEs murine models, including dextran sulfate sodium salt (DSS)-induced colitis murine model and a combined-ICIs-induced irAEs murine model. To further explore the applicability of our findings, murine models with graft-versus-host disease were established, in which Rag2-/-Il2rg-/- mice were transferred with human peripheral blood mononuclear cells and received combined cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) and programmed cell death protein-1 (PD-1) treatment. Human melanoma cells were xenografted into these mice concomitantly. RESULTS: Here we show that IL-23 was upregulated in the serum of patients suffering from irAEs after dual anti-CTLA-4 and anti-PD-1 treatment, and increased as a function of irAEs severity. Additionally, Augmented CD4+ Tems may preferentially underlie irAEs onset. Treating mice with anti-mouse IL-23 antibody concomitantly with combined CTLA-4 and PD-1 immunotherapy ameliorates colitis and, in addition, preserves antitumor efficacy. Moreover, in xenografted murine models with irAEs, prophylactic blockade of human IL-23 using clinically available IL-23 inhibitor (risankizumab) ameliorated colitis, hepatitis and lung inflammation, and moreover, immunotherapeutic control of tumors was retained. Finally, we also provided a novel machine learning-based computational framework based on two blood-based features-IL-23 and CD4+ Tems-that may have predictive potential for severe irAEs and ICIs response. CONCLUSIONS: Our study not only provides clinically feasible strategies to dissociate efficacy and toxicity in the use of combined ICIs for cancer immunotherapy, but also develops a blood-based biomarker that makes it possible to achieve a straightforward and non-invasive, detection assay for early prediction of irAEs onset.

Blockade of glucose-6-phosphate dehydrogenase induces immunogenic cell death and accelerates immunotherapy.

BACKGROUND: Enhanced glucose metabolism has been reported in many cancers. Glucose-6-phosphate dehydrogenase (G6PD) is a rate-limiting enzyme involved in the pentose phosphate pathway, which maintains NADPH levels and protects cells from oxidative damage. We recently found that low G6PD expression correlates with active tumor immunity. However, the mechanism involving G6PD and tumor immunity remained unclear. METHODS: We conducted in vitro studies using G6PD-knocked down malignant melanoma cells, pathway analysis using the GEO dataset, in vivo studies in combination with immune checkpoint inhibitors (ICIs) using a mouse melanoma model, and prognostic analysis in 42 melanoma patients and 30 lung cancer patients who were treated with ICIs. RESULTS: Inhibition of G6PD, both chemically and genetically, has been shown to decrease the production of NADPH and reduce their oxidative stress tolerance. This leads to cell death, which is accompanied by the release of high mobility group box 1 and the translocation of calreticulin to the plasma membrane. These findings suggested that inhibiting G6PD can induce immunogenic cell death. In experiments with C57BL/6 mice transplanted with G6PD-knockdown B16 melanoma cells and treated with anti-PD-L1 antibody, a significant reduction in tumor size was observed. Interestingly, inhibiting G6PD in only a part of the lesions increased the sensitivity of other lesions to ICI. Additionally, out of 42 melanoma patients and 30 lung cancer patients treated with ICIs, those with low G6PD expression had a better prognosis than those with high G6PD expression (p=0.0473; melanoma, p=0.0287; lung cancer). CONCLUSION: G6PD inhibition is a potent therapeutic strategy that triggers immunogenic cell death in tumors, significantly augmenting the efficacy of immunotherapies.

Case Series of Acral and Mucosal Melanoma in a Diverse Patient Population.

Melanomas affecting acral and mucosal sites have distinct features and are associated with poorer prognosis. Patients of color may be disproportionately affected. Herein we discuss six ethnically diverse cases of acral and mucosal melanoma (AMM). More data on clinical, genetic, and environmental features of AMM are needed, but thorough physical examination can reduce the burden of disease now. J Drugs Dermatol. 2024;23(8):683-685. doi:10.36849/JDD.8311.

Investigating the impact of exercise on T and NK cells in skin cancer: a systematic review.

Skin cancer has the highest incidence of all cancers, and their incidence are increasing in both melanoma and non-melanoma skin cancers. Alternative adjuvant treatment strategies appropriate for their management are needed. Modifiable lifestyle factors influence disease outcomes, either improving or worsening outcomes. Exercise is an example of a modifiable lifestyle factor, and can be prescribed as an adjuvant therapy in other cancer types to improve immune function and overall clinical outcomes. The initial aim of the review was to investigate the T-cell specific mechanisms of exercise which affect clinical/disease outcomes in skin cancer. Study quality was assessed by a modified Covidence quality assessment template with animal-model study specific criteria. A total of 10 articles were included; all articles were murine model studies investigating melanoma. Eight studies (n=8) employed a randomised controlled trial design, with two bio-informatics studies, and one study using human data which could solidify a link to human health. While the review focussed initially on T-cells, many studies reported significant changes in NK cells, and as they share the same haematopoietic lineage/ common lymphoid progenitor as T cells, the data was included in the analyses. Most studies indicated that exercise reduced melanoma tumour burden. Exercising prior to melanoma inoculation was most effective for delaying carcinogenesis and reducing tumour burden. Synergism was a topic identified in studies; PD-1/PD-L1 treatment, and exercise were not synergistic. Conversely, exercise and mental stimulation were synergistic, and the temperature at which exercise was conducted significantly reduced tumour burden. Several murine studies reported that exercise improved clinical outcomes in melanoma, and that long-term exercise was more effective in reducing tumour burden. Further studies are required to investigate this relationship in humans, and in other types of skin cancer.

Skin procedures in general practice.

BACKGROUND: Most skin cancers diagnosed in Australia, including melanomas, are identified and managed in a primary care setting. Most skin cancers have the diagnosis confirmed by histopathology, and surgical excision is the most common form of treatment. Therefore, it is important that all primary care doctors in Australia are competent and confident in the diagnostic sampling and surgical management of skin cancers. OBJECTIVE: This article considers the process of performing biopsies and excisions from the skin to diagnose or treat skin cancers. DISCUSSION: Primary care is the appropriate setting for the management of most skin cancers in Australia. Small simple lesions can be sampled for diagnosis and excised as definitive treatment of the tumour. This can be simpler, cheaper and more efficient for the patient compared to the hospital setting, allows the resources of speciality care to be used for more difficult scenarios and be quite a satisfying part of providing primary care.

The Efficacy of Curcumin Application to Melanoma in Mice: A Systematic Review and Meta-analysis.

OBJECTIVE: Melanoma is a skin tumor that poses a serious threat to human health. Our study explores the effectiveness and safety of curcumin in the treatment of melanoma based on animal models, and providing evidence-based medical evidence for curcumin in the treatment of malignant melanoma. METHODS: The study collected all randomized controlled trial data from the establishment of the database to October 2023 of curcumin for the treatment of melanoma in mice by searching PubMed, Embase, and the Cochrane Library. According to inclusion and exclusion criteria, data were extracted and quality assessment of included studies was performed by using the SYRCLE (Systematic Review Center for Laboratory animal Experimentation) animal experiment bias risk assessment tool. RevMan 5.4 and Stata 15.1 software were used for meta-analysis. RESULTS: Eighteen randomized controlled trials were included in this study with a total of 185 mouse models, including 93 mice in the experimental group and 92 in the control group. The results of meta-analysis showed that the IC50 (inhibitory concentrations of 50%) in the experimental group is lower than that of the control group [standardized mean difference (SMD) = -4.68, 95% confidence interval (CI) (-7.30, -2.06), P < 0.01]; the tumor volume is significantly smaller than the control group [SMD = -3.10, 95% CI (-4.45, -1.75), P < 0.01]; the tumor weight is smaller than the control group [SMD = -3.01, 95% CI (-4.81, -1.21), P < 0.01]. However, there was no significant statistical difference in the apoptosis rate between the experimental group and the control group [SMD = 2.27, 95% CI (-1.39, 5.92), P < 0.01]. CONCLUSION: Based on animal models for meta-analysis, curcumin can inhibit the growth and proliferation of melanoma in mice. Melanoma may be an effective method for treating melanoma. However, this result still requires further in-depth research.

The Role of Surgery for Stage IV Melanoma.

Historically, stage IV melanoma carried a dismal prognosis and surgical resection was the only potential treatment offering long-term survival or palliation of symptomatic disease. With modern systemic therapies that can provide durable disease control for many patients with metastatic disease, we are actively redefining the role of surgery in metastatic melanoma. Contemporary treatment strategies can employ surgical resection in the upfront setting followed by adjuvant therapy, or used in tailored approach following systemic therapy. The combination of surgical resection and modern therapies has been associated with good long-term survival.

Tumor-derived GLI1 promotes remodeling of the immune tumor microenvironment in melanoma.

BACKGROUND: Melanoma progression is based on a close interaction between cancer cells and immune cells in the tumor microenvironment (TME). Thus, a better understanding of the mechanisms controlling TME dynamics and composition will help improve the management of this dismal disease. Work from our and other groups has reported the requirement of an active Hedgehog-GLI (HH-GLI) signaling for melanoma growth and stemness. However, the role of the downstream GLI1 transcription factor in melanoma TME remains largely unexplored. METHODS: The immune-modulatory activity of GLI1 was evaluated in a syngeneic B16F10 melanoma mouse model assessing immune populations by flow cytometry. Murine polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) were differentiated from bone marrow cells and their immunosuppressive ability was assessed by inhibition of T cells. Conditioned media (CM) from GLI1-overexpressing mouse melanoma cells was used to culture PMN-MDSCs, and the effects of CM were evaluated by Transwell invasion assay and T cell inhibition. Cytokine array analysis, qPCR and chromatin immunoprecipitation were performed to explore the regulation of CX3CL1 expression by GLI1. Human monocyte-derived dendritic cells (moDCs) were cultured in CM from GLI1-silenced patient-derived melanoma cells to assess their activation and recruitment. Blocking antibodies anti-CX3CL1, anti-CCL7 and anti-CXCL8 were used for in vitro functional assays. RESULTS: Melanoma cell-intrinsic activation of GLI1 promotes changes in the infiltration of immune cells, leading to accumulation of immunosuppressive PMN-MDSCs and regulatory T cells, and to decreased infiltration of dendric cells (DCs), CD8 + and CD4 + T cells in the TME. In addition, we show that ectopic expression of GLI1 in melanoma cells enables PMN-MDSC expansion and recruitment, and increases their ability to inhibit T cells. The chemokine CX3CL1, a direct transcriptional target of GLI1, contributes to PMN-MDSC expansion and recruitment. Finally, silencing of GLI1 in patient-derived melanoma cells promotes the activation of human monocyte-derived dendritic cells (moDCs), increasing cytoskeleton remodeling and invasion ability. This phenotype is partially prevented by blocking the chemokine CCL7, but not CXCL8. CONCLUSION: Our findings highlight the relevance of tumor-derived GLI1 in promoting an immune-suppressive TME, which allows melanoma cells to evade the immune system, and pave the way for the design of new combination treatments targeting GLI1.

Establishment of a CD8+ T cells-related prognostic risk model for acral melanoma based on single-cell and bulk RNA sequencing.

BACKGROUND: CD8+ T cells have been recognized as crucial factors in the prognosis of melanoma. However, there is currently a lack of gene markers that accurately describe their characteristics and functions in acral melanoma (AM), which hinders the development of personalized medicine. METHODS: Firstly, we explored the composition differences of immune cells in AM using single-cell RNA sequencing (scRNA-seq) data and comprehensively characterized the immune microenvironment of AM in terms of composition, developmental differentiation, function, and cell communication. Subsequently, we constructed and validated a prognostic risk scoring model based on differentially expressed genes (DEGs) of CD8+ T cells using the TCGA-SKCM cohort through Lasso-Cox method. Lastly, immunofluorescence staining was performed to validate the expression of four genes (ISG20, CCL4, LPAR6, DDIT3) in AM and healthy skin tissues as included in the prognostic model. RESULTS: The scRNA-seq data revealed that memory CD8+ T cells accounted for the highest proportion in the immune microenvironment of AM, reaching 70.5%. Cell-cell communication analysis showed extensive communication relationships among effector CD8+ T cells. Subsequently, we constructed a prognostic scoring model based on DEGs derived from CD8+ T cell sources. Four CD8+ T cell-related genes were included in the construction and validation of the prognostic model. Additionally, immunofluorescence results demonstrated that ISG20 and CCL4 were downregulated, while LPAR6 and DDIT3 were upregulated in AM tissues compared to normal skin tissues. CONCLUSION: Identifying biomarkers based on the expression levels of CD8+ T cell-related genes may be an effective approach for establishing prognostic models in AM patients. The independently prognostic risk evaluation model we constructed provides new insights and theoretical support for immunotherapy in AM.

Artificial intelligence-assisted metastasis and prognosis model for patients with nodular melanoma.

OBJECTIVE: The objective of this study was to identify the risk factors that influence metastasis and prognosis in patients with nodular melanoma (NM), as well as to develop and validate a prognostic model using artificial intelligence (AI) algorithms. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was queried for 4,727 patients with NM based on the inclusion/exclusion criteria. Their clinicopathological characteristics were retrospectively reviewed, and logistic regression analysis was utilized to identify risk factors for metastasis. This was followed by employing Multilayer Perceptron (MLP), Adaptive Boosting (AB), Bagging (BAG), logistic regression (LR), Gradient Boosting Machine (GBM), and eXtreme Gradient Boosting (XGB) algorithms to develop metastasis models. The performance of the six models was evaluated and compared, leading to the selection and visualization of the optimal model. Through integrating the prognostic factors of Cox regression analysis with the optimal models, the prognostic prediction model was constructed, validated, and assessed. RESULTS: Logistic regression analyses identified that marital status, gender, primary site, surgery, radiation, chemotherapy, system management, and N stage were all independent risk factors for NM metastasis. MLP emerged as the optimal model among the six models (AUC = 0.932, F1 = 0.855, Accuracy = 0.856, Sensitivity = 0.878), and the corresponding network calculator (https://shimunana-nm-distant-m-nm-m-distant-8z8k54.streamlit.app/) was developed. The following were examined as independent prognostic factors: MLP, age, marital status, sequence number, laterality, surgery, radiation, chemotherapy, system management, T stage, and N stage. System management and surgery emerged as protective factors (HR < 1). To predict 1-, 3-, and 5-year overall survival (OS), a nomogram was created. The validation results demonstrated that the model exhibited good discrimination and consistency, as well as high clinical usefulness. CONCLUSION: The developed prediction model more effectively reflects the prognosis of patients with NM and differentiates between the risk level of patients, serving as a useful supplement to the classical American Joint Committee on Cancer (AJCC) staging system and offering a reference for clinically stratified individualized treatment and prognosis prediction. Furthermore, the model enables clinicians to quantify the risk of metastasis in NM patients, assess patient survival, and administer precise treatments.

[Anorectal melanoma: Clinical case]. / Melanoma anorrectal: un caso clínico.

Background: Anorectal melanoma (AM) is a rare and aggressive type of tumor, with varied and inconclusive scientific information. Its preoperative diagnosis is challenging due to its rarity and similarity to other anorectal conditions. It represents only 1.3% of melanomas and affects more women than men. Approximately 20-30% of AM cases are amelanotic, complicating endoscopic detection and leading to misdiagnoses. AM is often confused with hemorrhoids, polyps, and rectal cancer in two thirds of patients due to similar symptoms. The causes and risk factors of AM are not well understood, but they are suspected to differ from cutaneous and ocular melanomas. Diagnosis is performed through biopsy and immunohistochemical staining. Colonoscopy helps to characterize the lesions, and histological examination is crucial for definitive diagnosis. Clinical case: 50-year-old woman with rectal bleeding and proctalgia. AM was diagnosed through colonoscopy, and transanal resection with hemorrhoidectomy was performed. Conclusions: Management of AM is complicated by the lack of randomized trials. Resection surgery is the standard treatment, but there is no established protocol. Wide local excision may be an option for limited cases. Further research is needed to improve the management and treatment of AM. Early detection and complete surgical removal are crucial for enhancing survival in these patients.

Introducción: el melanoma anorrectal (MA) es un tipo raro y agresivo de tumor, cuya información científica es variada y poco concluyente. Su diagnóstico preoperatorio es un desafío debido a su rareza y a su similitud con otras afecciones anorrectales. Representa solo el 1.3% de los melanomas y afecta más a mujeres que a hombres. Aproximadamente el 20-30% de los casos de MA son amelanóticos, lo que complica su detección endoscópica y conduce a diagnósticos erróneos. El MA se confunde con hemorroides, pólipos y cáncer de recto en dos tercios de los pacientes debido a síntomas similares. Las causas y factores de riesgo del MA aún no se conocen bien, pero se sospecha que son diferentes de los melanomas cutáneos y oculares. El diagnóstico se realiza mediante biopsia y tinción inmunohistoquímica. La colonoscopía permite caracterizar las lesiones y el examen histológico es crucial para el diagnóstico definitivo. Caso clínico: mujer de 50 años con rectorragia y proctalgia. Se diagnosticó MA mediante colonoscopía y se realizó una resección transanal con hemorroidectomía. Conclusiones: el manejo del MA es complicado por la falta de ensayos aleatorizados. La cirugía de resección es el tratamiento habitual, pero no hay un protocolo establecido. La escisión local amplia puede ser una opción para casos limitados. Se necesita más investigación para mejorar el manejo y tratamiento del MA. La detección temprana y la extirpación quirúrgica completa son cruciales para mejorar la supervivencia en estos pacientes.

Development and piloting of an online course to improve knowledge, confidence and attitudes towards triaging images of skin lesions submitted online in primary care.

BACKGROUND: Melanoma is the 5th commonest cancer in the UK and survivors require frequent and thorough skin checks. During the Achieving Self-directed Integrated Cancer Aftercare (ASICA) trial, melanoma survivors used an app to submit images of concerning lesions for assessment by a dermatology nurse. In the past, online courses have been used to train non-specialist primary care practitioners (PCPs) in this skill. OBJECTIVES: This study aimed to determine whether an online course could increase knowledge, confidence, and attitudes towards skin image triage in PCPs in the Grampian area. METHODS: Preliminary discussions were held with PCPs to determine the need for an online course. The course was designed at the University of Aberdeen and included an introduction to the skin, case studies and quizzes on a variety of skin conditions based on melanoma survivors' submissions via the ASICA app. Two pre- and post-course questionnaires were administered to all participants to (1) assess knowledge gained and (2) assess any improvements in confidence and attitudes towards triaging skin lesions that could be indicative of skin cancer. All PCPs in the Grampian area were invited to participate with almost 70 medical practices contacted. Results were analysed using a paired sample T-test. RESULTS: The course was advertised to all GP practices in the Grampian area and 38 PCPs completed all its stages. Undertaking the course improved all PCPs' confidence and attitudes towards triaging (p < 0.001). It also improved knowledge in all non-GP PCPs (p = 0.01). Most participants found the course useful; thought it was at the right level of difficulty, right format and thought the design was good. CONCLUSIONS: Our online course in triaging skin lesions submitted digitally to PCPs was able to improve knowledge, confidence, and attitudes towards triaging. The course was acceptable in its design and was deemed useful and applicable to practice. Further research should investigate the effect the course has on secondary care referral numbers.

Tumour-intrinsic endomembrane trafficking by ARF6 shapes an immunosuppressive microenvironment that drives melanomagenesis and response to checkpoint blockade therapy.

Tumour-host immune interactions lead to complex changes in the tumour microenvironment (TME), impacting progression, metastasis and response to therapy. While it is clear that cancer cells can have the capacity to alter immune landscapes, our understanding of this process is incomplete. Herein we show that endocytic trafficking at the plasma membrane, mediated by the small GTPase ARF6, enables melanoma cells to impose an immunosuppressive TME that accelerates tumour development. This ARF6-dependent TME is vulnerable to immune checkpoint blockade therapy (ICB) but in murine melanoma, loss of Arf6 causes resistance to ICB. Likewise, downregulation of ARF6 in patient tumours correlates with inferior overall survival after ICB. Mechanistically, these phenotypes are at least partially explained by ARF6-dependent recycling, which controls plasma membrane density of the interferon-gamma receptor. Collectively, our findings reveal the importance of endomembrane trafficking in outfitting tumour cells with the ability to shape their immune microenvironment and respond to immunotherapy.

Shave procedures in the management of skin lesions where melanoma is a differential diagnosis.

BACKGROUND: Australia has the world's highest melanoma incidence. Diagnostic aids improve melanoma diagnosis, but most lesions excised on suspicion of being melanoma are benign. Reliance on formal ellipse is common. OBJECTIVE: We explore the utility of shave procedures in melanoma management. DISCUSSION: The topic of shave procedures in the management of melanoma is controversial and attracts strongly held views both for and against. The available data shows that shaves can be employed safely and produce an acceptable cosmetic outcome with low financial costs while also being a time-efficient procedure both for the patient and the clinician alike.

Chemical complementarity of tumor resident, T-cell receptor CDR3s and renalase-1 correlates with increased melanoma survival.

Overexpression of the secretory protein renalase-1 negatively impacts the survival of melanoma and pancreatic cancer patients, while inhibition of renalase-1 signaling drives tumor rejection by promoting T-cell activation. Thus, we investigated the chemical complementarity between melanoma-resident, T-cell receptor (TCR) complementarity-determining region 3 (CDR3) amino acid sequences (AAs) and the renalase-1 protein. Increasing complementarity of TCR CDR3s to renalase-1 AAs, as assessed by a chemical complementarity scoring algorithm, was associated with improved overall survival (OS) in melanoma patients. The expression levels of several immune signature genes were significantly, positively correlated with increasing TCR CDR3-renalase-1 complementarity scores. Additionally, the survival association observed with high complementarity of TCR CDR3s to renalase-1 AAs was more robust in cases with low renalase-1 gene expression levels. Mapping of TCR CDR3-renalase-1 in silico interaction sites identified major epitope candidates including RP220, the signaling module of the renalase-1 protein, consistent with the fact that a monoclonal antibody to RP220 is a potent inhibitor of melanoma growth. These findings indicate that renalase-1 is a potential antigen for TCR recognition in melanoma and could be considered as a target for immunotherapy.

[ALK rearranged Spitz melanocytoma: a clinicopathological and molecular genetic analysis of two cases].

Objective: To investigate the clinicopathological, immunohistochemical and molecular characteristics of cutaneous ALK-rearranged Spitz melanocytoma. Methods: Two cases of cutaneous ALK-rearranged Spitz melanocytoma from outside hospital consultations in Department of Pathology, Affiliated Cancer Hospital of Fudan University in August 2020 and in Shanghai Ackermann Medical Laboratory in June 2022 were collected. The clinicopathological features, immunophenotypes and molecular profiles of two patients with cutaneous Spitzoid melanocytic tumor harboring ALK-rearrangement were analyzed. The literatures were reviewed. Results: The study included an 8-year-old boy and an 11-year-old girl, who presented with a polypoid lesion in the skin of right thigh and left auricle measuring 1.0 cm and 1.2 cm, respectively. Histologically, they were composed of medium to large-sized epithelioid to plump spindle cells, arranged in nested, plexiform or fascicular patterns in the superficial dermis. The neoplastic cells had abundant eosinophilic cytoplasm with round to ovoid vesicular nuclei containing prominent eosinophilic nucleoli. One case showed mild to moderate nuclear pleomorphism and mitotic activity (average, 2/mm2). Immunohistochemically, the epithelioid and plump spindle cells showed diffuse and strong staining of S-100 protein, SOX10, and ALK (D5F3 and 1A4), but did not express HMB45, PNL2 and MiTF. ALK-rearrangement was detected by fuorescence in situ hybridization in both cases. Subsequent next generation sequence (NGS) analysis identified KANK1::ALK and TPM3:ALK fusions. At 34 and 14 months after surgical resection, both patients remained well with no signs of recurrence or metastasis. Conclusions: ALK-rearranged Spitz melanocytoma represents a morphologically and genetically distinct subset of Spitz melanocytoma, characterized clinically by predilection in children and adolescents, with Spitzoid morphology in plexiform pattern, positive immunohistochemical stains, and rearrangement of ALK. As some cases show atypical features and high mitotic activity, a distinction from Spitz melanoma is warranted.

[Clinicopathological features of metastatic melanoma in effusion cytology of serosal cavity].

Objective: To investigate the clinical, cytomorphology, immunocytochemical and molecular features of metastatic melanoma in serosal cavity effusion. Methods: Cytological specimens of 14 patients with melanoma in the chest and abdomen were collected from 2017 to 2023, at the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. SOX10, S-100 protein, PRAME, BRAF V600E, HMB45, and Melan A were detected by immunocytochemical methods. Fourteen cases were tested for routine antibody combinations, including Claudin4, HEG1, Calretinin, CD68, etc. Four of the patients had biopsy or surgical samples of metastatic solid lesions of primary sites, and further next-generation sequencing (NGS) or amplification refractory mutation system (ARMS)-PCR molecular test was performed. In addition, 30 cases of serosal effusion samples were collected as control groups (10 cases of benign mesothelial cell reactive hyperplasia, 10 cases of mesothelioma, and 10 cases of metastatic lung adenocarcinoma). Results: Among the 14 cases of melanoma, there were 7 males and 7 females, with ages ranging from 35 to 86 years, and an average age of 57 years, there 10 cases aged ≥50 years. The tumor cells in the serosal effusion varied in morphology and degree of atypia. SOX10 was positive in all 14 cases (14/14), S-100 protein was positive in 10 cases (10/14), PRAME was positive in 12 cases (12/14), BRAF V600E was positive in 10 cases (10/14), HMB45 was positive in 12 cases (12/14), and Melan A was positive in 13 cases (13/14). In 4 patients with histological correlation, the cytological and histological expression of SOX10, BRAF V600E, and PRAME was positive in all 4 cases (4/4); S-100 protein was positive in 2 cases (2/4); and HMB45 and Melan A were positive in 3 cases (3/4). Using NGS or ARMS-PCR, missense mutations of BRAF V600E were detected in all 4 patients; TERT promoter mutations was detected in 1 case; and CDKN2A terminating mutations and MSI1 deletion mutations were detected in the other case. SOX10, S-100, HMB45, Melan A, PRAME and BRAF V600E were all negative in 30 control samples of serosal cavity effusion. Conclusion: By observing the morphology of tumor cells, immunocytochemical test of several combination markers, especially the expression of SOX10, BRAF V600E and PRAME, can help to improve the positive diagnosis rate of melanoma in serous cavity effusion.