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Abstract: Although CD20 expression is typically scarce in mycosis fungoides (MF), it is more commonly associated with T-cell lymphomas. Nevertheless, isolated instances of CD20-positive MF have been documented infrequently. Here, we present a unique case of CD20-positive MF in a 30-year-old man who manifested with a hypopigmented patch on the anterior chest. Histopathological examination revealed epidermotropic infiltrates of small- to medium-sized lymphocytes with hyperchromatic and cerebriform nuclei aligned along the basal and low-mid layers of the epidermis. Immunophenotypic analysis demonstrated neoplastic T cells expressing CD4+, CD8+, and CD3+ with the loss of CD7. Intriguingly, a notable subset of the neoplastic T cells exhibited CD20 expression. This case contributes to the sparse literature on CD20-positive MF and underscores its diagnostic and clinical ramifications. The role of B cells has been more thoroughly characterized in T-cell lymphomas other than MF. However, its significance in MF remains unclear due to the scarcity of reported cases. Some hypotheses propose that the B cells' expression might indicate immune dysregulation or complex interactions within the tumor microenvironment. Another perspective suggests it could signify a progression of the disease towards a more aggressive lymphoma phenotype. Further investigation and documentation of similar cases is imperative to elucidate the clinical features, prognosis, and optimal therapeutic strategies. The long-term prognosis and outcomes in patients with hypopigmented MF and CD20 positivity remain ambiguous, underscoring the necessity for continued research and scrutiny of analogous cases., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Mycosis fungoides (MF) represents the most common type of primary cutaneous T-cell lymphoma. Recognition of MF variants with divergent immunophenotypes is important for accurate diagnosis and appropriate management, as they can be confused with other lymphoma subtypes. We present a case of a 49-year-old male previously diagnosed with a cutaneous lymphoproliferative disorder with an unusual NK/T-cell phenotype. He presented with a 10-year history of pelvic girdle rash involving the right hip and upper thigh. The lesions were characterized as atrophic patches concentrated in sun-protected areas and involving 10% of the body surface area. Shave biopsies revealed an atypical epidermotropic infiltrate composed of hyperchromatic small to medium-sized lymphocytes with perinuclear halos and "tagging" along the dermal-epidermal junction. The immunophenotype was unusual in that the neoplastic lymphocytes showed complete loss of pan T-cell antigens along with expression of CD56, cytotoxic markers, and weak CD20. All other B-cell markers were negative. The combination of clinical findings, in addition to the histopathologic and immunophenotypic profile, were diagnostic of null T-cell phenotype MF with aberrant expression of CD56 and CD20. Null T-cell phenotype MF is very uncommon, can be diagnostically challenging, and can mislead the diagnosis of aggressive lymphoma subtypes., (© 2024 The Authors. Journal of Cutaneous Pathology published by John Wiley & Sons Ltd.)

The oncogene PIM2 is upregulated in several malignancies but has never been investigated in mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma (CTCL). PIM2 is a well-known oncogene and is regulated by cell signaling pathways like the JAK/STAT- and NF-kB-pathway, key regulators in the pathogenesis of CTCL. The aim of this study was to examine the role of PIM2 in MF. PIM2 gene expression was measured in 81 formalin-fixed paraffin-embedded skin biopsies from patients with MF and 46 control biopsies from healthy skin (HS) and benign inflammatory skin disease (BID). Validation of PIM2 protein expression was performed on selected biopsies with immunohistochemical staining. We found a significant difference in gene expression levels between both early stage MF and HS (p < 0.0001), and BID (p < 0.0001). In addition, the PIM2 gene expression was higher in advanced-stage MF compared to early stage disease (p = 0.0001). No significant difference in gene expression levels was found between patients with and without disease progression. In conclusion, we found PIM2 expression is significantly increased in MF compared to controls, and in advanced-stage MF compared to early stage MF. These findings could potentially have diagnostic value in discriminating early stage MF from BID., (© 2024 Scandinavian Societies for Pathology, Medical Microbiology and Immunology.)

Abstract: Sézary syndrome (SS) is an aggressive leukemic expansion of skin-derived malignant CD4+ T cells. Drug monotherapy often results in disease relapse because of the heterogenous nature of malignant CD4+ T cells, but how therapies can be optimally combined remains unclear because of limitations in understanding the disease pathogenesis. We identified immunologic transitions that interlink mycosis fungoides with SS using single-cell transcriptome analysis in parallel with high-throughput T-cell receptor sequencing. Nascent peripheral CD4+ T cells acquired a distinct profile of transcription factors and trafficking receptors that gave rise to antigenically mature Sézary cells. The emergence of malignant CD4+ T cells coincided with the accumulation of dysfunctional monocytes with impaired fragment crystallizable γ-dependent phagocytosis, decreased responsiveness to cytokine stimulation, and limited repertoire of intercellular interactions with Sézary cells. Type I interferon supplementation when combined with a monoclonal antibody targeting the chemokine receptor type 4 (CCR4), unleashed monocyte induced phagocytosis and eradication of Sézary cells in vitro. In turn, coadministration of interferon-α with the US Food and Drug Administration-approved anti-CCR4 antibody, mogamulizumab, in patients with SS induced marked depletion of peripheral malignant CD4+ T cells. Importantly, residual CD4+ T cells after Sézary cell ablation lacked any immunologic shifts. These findings collectively unveil an auxiliary role for augmenting monocytic activity during mogamulizumab therapy in the treatment of SS and underscore the importance of targeted combination therapy in this disease., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Background: Mycosis fungoides (MF) is a chronic, highly recurrent cutaneous T-cell lymphoma, whose pathogenesis has not yet been fully elucidated. Interleukin-15 was previously highlighted as a viability factor for cutaneous T-cell lymphoma with previous studies shedding light on its role in pathogenesis of MF and its plausibility as a potential therapeutic target., Objective: This study was conducted to evaluate serum and tissue expression of IL-15 and IL-15Rα in early cases of MF (IA, IB, IIA) at baseline and following phototherapy., Materials and Methods: Fourteen early MF cases were recruited. Samples were withdrawn prior to starting phototherapy treatment and following near complete clearance of the biopsied lesion or after a maximum of 36 sessions of phototherapy. Samples were assessed for change in expression of IL-15 and IL-15 Rα levels following treatment, whose levels were compared to healthy controls., Results: Serum and tissue levels of IL-15 and IL-15Rα in early MF cases were significantly higher at baseline than their levels following phototherapy treatment and higher than healthy controls. However, they dropped significantly following treatment with no statistical difference between treated cases and controls, apart from serum IL-15Rα that remained significantly elevated than controls., Conclusion: Interleukin-15 and its receptor alpha appear to contribute to the pathogenesis of MF, being significantly elevated than healthy controls, which were normalized following phototherapy treatment, apart from serum IL-15Rα, which remained elevated. Controlling IL-15/IL-15Rα expression is a newly proposed mechanism of action of phototherapy in MF., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Discriminating between cutaneous anaplastic large cell lymphoma (cALCL) and CD30-positive transformed mycosis fungoides (CD30+ TMF) is challenging, particularly when they arise in the context of pre-existing mycosis fungoides. The development of molecular diagnostic tools was hampered by the rarity of both diseases and the limited understanding of their pathogenesis., Methods: In this study, we established a cohort comprising 25 cALCL cases and 25 CD30+ TMF cases, with transcriptomic data obtained from 31 samples. We compared the clinicopathological information and investigated the gene expression profiling between these two entities. Furthermore, we developed an immunohistochemistry (IHC) algorithm to differentiate these two entities clinically., Results: Our investigation revealed distinct clinicopathological features and unique gene expression programs associated with cALCL and CD30+ TMF. cALCL and CD30+ TMF displayed marked differences in gene expression patterns. Notably, CD30+ TMF demonstrated enrichment of T cell receptor signaling pathways and an exhausted T cell phenotype, accompanied by infiltration of B cells, dendritic cells, and neurons. In contrast, cALCL cells expressed high levels of HLA class II genes, polarized towards a Th17 phenotype, and exhibited neutrophil infiltration. An IHC algorithm with BATF3 and TCF7 staining emerged as potential diagnostic markers for identifying these two entities., Conclusions: Our findings provide valuable insights into the differential molecular signatures associated with cALCL and CD30+ TMF, which contribute to their distinct clinicopathological behaviors. An appropriate IHC algorithm could be used as a potential diagnostic tool., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lai, Liu, Liu, Sun and Wang.)

Background: European studies suggest an association between cutavirus (CuV) and cutaneous T-cell lymphoma (CTCL); however, the worldwide prevalence of CuV in patients with CTCL and its prognostic impact remain unknown., Methods: We investigated the prevalence and viral loads of CuV DNA using biopsy specimens from the lesional skins of 141 Japanese patients with cutaneous malignancies, including 55 patients with various types of CTCL., Results: CuV DNA was detected significantly more frequently in biopsies from patients with mycosis fungoides (MF) (38% [13/34]; the most common subtype of CTCL) than in those from patients with other cutaneous malignancies (6% [6/107]; P<0.001). The viral-load range in patients with CuV DNA-positive MF was 23-3922 copies/10 3 cells and 8-65 copies/μg of DNA. A phylogenetic analysis using the partial sequences of the CuV viral capsid protein 1 (VP1)/VP2 genes revealed that the CuV sequences identified here were clustered in a Japanese-specific clade distinct from that comprising CuV sequences from European patients with MF. Kaplan-Meier curves and a log-rank test showed that CuV positivity was associated with a shorter disease-specific survival in patients with MF (P = 0.031), whereas no significant difference in overall survival was observed (P = 0.275). No significant correlation was observed between CuV DNA load and survival in patients with CuV-positive MF., Conclusions: Our results suggest that CuV is associated with MF in a subset of Japanese patients. Large-scale prospective studies are warranted to clarify the role of CuV status, especially regarding the viral genotype, on adverse outcomes in patients with CuV-positive MF., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Mycosis Fungoides (MF) is a common cutaneous T-cell lymphoma. It can sometimes be challenging to diagnose MF using current clinico-histopathological criteria. Non-invasive molecular profiling analysis has the potential to aid the diagnosis and understanding of MF., Method: Lesional and body site matched normal stratum corneum samples were obtained from the same MF patients (n = 28) using adhesive discs, followed by proteomic analyses using data-independent acquisition mass spectrometry (DIA-MS). Differential abundance analyses and bioinformatic analyses were performed to identify differentially abundant proteins and altered biofunctions between the MF and normal stratum corneum samples., Results: In total, 1303 proteins were identified, of which 290 proteins were significantly changed in the MF cohort compared to the normal stratum corneum. Ingenuity pathway analysis (IPA) predicted the significant inhibition of cell death of cancer cells and significant activation of immune-related activities and viral infection in the MF lesions. MF lesions were also associated with upstream regulators relating to immuno-oncologic dysfunctions. The top-250 variating proteins efficiently separated normal stratum corneum from matched MF samples., Conclusion: Non-invasive proteomic analysis could transform the diagnosis of MF by reducing the need for invasive biopsy. The identification of altered biological functions may serve as useful biomarkers to predict MF progression., (© 2023 The Authors. Proteomics - Clinical Applications published by Wiley-VCH GmbH.)

Background: Mycosis fungoides (MF) is considered the commonest type of cutaneous T-cell lymphoma representing about 50% of all primary cutaneous lymphomas. Differentiation between MF and another inflammatory dermatitis (BIDs) is important to ensure proper management., Aim: We aimed to evaluate the immunohistochemical expression of T OX, ICOS, and GATA binding protein 3 (GATA-3) in early stages MF (stage IA and IB) to establish their diagnostic value and to guide the use of inhibitors in the treatment of cutaneous T-cell lymphomas., Materials and Methods: A retrospective study of 75 skin paraffin blocks (punch biopsy) 40 cases of MF and 35 cases of eczematous dermatitis as a group representing other inflammatory dermatitis were retrieved from archives of the pathology department of our University, during the period from October 2017 to May 2021., Results: About 98% and 90% of patients in the MF group had positive T OX and ICOS, while 70% of them had positive GATA-3. High expression of T OX, ICOS, and GATA-3 was associated with higher stages., Conclusions: T OX is considered a diagnostic marker for early MF. The importance of identifying novel markers in MF expressed by immunohistochemistry, such as ICOS, has been established. According to our results, GATA-3 could be used as an accessory marker in the diagnosis of MF when combined with T OX and ICOS in a panel., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Mycosis fungoides (MF) is the most common type of cutaneous lymphoma. The early stage of MF is a difficult diagnostic case, as it is often confused with many benign inflammatory dermatoses (BID). The study aimed to evaluate the diagnostic utility of TOX, FOXP3, CDD4 and GATA3 in differentiating early stages of MF from histologically overlapping BID lesions., Material and Method: A retrospective cross-sectional study was performed, in which immunohistochemistry (IHC) was used to evaluate the expression of TOX, FOXP3, CD4 and GATA3 in formalin-fixed paraffin-embedded (FFPE) sections of skin lesions from 30 cases with BID and 30 patients with early-stage MF., Results: The association between TOX expression and early-stage MF was statistically significant (P < 0.001). TOX had the highest sensitivity of 96.77% and accuracy of 85.71% in diagnosis of MF; followed by CD4 with sensitivity of 85.71% and accuracy of 78.95%; and then, GATA3 with sensitivity of 76.7% and finally FOXP3 with sensitivity of 70.0%., Conclusion: TOX is suggested to be of higher diagnostic value in the early stages of MF than the conventionally used CD4 and other markers examined.

Background: The mechanisms involved in mycosis fungoides, and Sezary Syndrome progression are largely unknown. Over the last decade the interest in immune system contrast of neoplasm has grown owing to the introduction of immunotherapy. PD-1 and its ligand (PD-L1) are the target of several immunotherapy treatment. In the literature reports on the expression of PD-1 and PD-L1 have provided contrasting results., Methods: In our analysis we investigated PD-1 expression in neoplastic cells and in tumor infiltrating lymphocytes (TILs) as well as PD-L1 expression in tumor cells and in tumor associated macrophages (TAMs). PD-L1 and PD-1 positive cells were counted in 5 high-power fields (HPF) and scored as the average number of positive neoplastic cells/TILs/TAMs per HPF., Results: From databases of two institutions (Bologna and Florence) thirty-five patients corresponding to 43 biopsies were retrieved. In seven instances sequential biopsies were present. No statistically significant expression was observed comparing early to advanced stages by analysing PD-1 by tumor cells and TILs and of PD-L1 by tumor cells and TAMs., Conclusions: Our results corroborate that PD-1 and PD-L1 expression is not stage-dependent in mycosis fungoides and Sezary syndrome. However, PD-1 and PD-L1 expression in affected patients provides a rationale to schedule anti PD-1/PD-L1 drugs.

Mycosis fungoides (MF) is the most common subtype of cutaneous T-cell lymphoma. Early-stage disease is characterized by superficial infiltrates of small- to medium-sized atypical epidermotropic T lymphocytes that are clonal related. Nevertheless, the percentage of atypical T cells is low with many admixed reactive immune cells. Despite earlier studies, the composition and spatial characteristics of the cutaneous lymphocytic infiltrate has been incompletely characterized. Here, we applied mass cytometry to profile the immune system in skin biopsies of patients with early-stage MF and in normal skin from healthy individuals. Single-cell suspensions were prepared and labeled with a 43-antibody panel, and data were acquired on a Helios mass cytometer. Unbiased hierarchical clustering of the data identified the major immune lineages and heterogeneity therein. This revealed patient-unique cell clusters in both the CD4 + and myeloid cell compartments but also phenotypically distinct cell clusters that were shared by most patients. To characterize the immune compartment in the tissue context, we developed a 36-antibody panel and performed imaging mass cytometry on MF skin tissue. This visualized the structure of MF skin and the distribution of CD4 + T cells, regulatory T cells, CD8 + T cells, malignant T cells, and various myeloid cell subsets. We observed clusters of CD4 + T cells and multiple types of dendritic cells (DCs) identified through differential expression of CD11c, CD1a, and CD1c in the dermis. These results indicated substantial heterogeneity in the composition of the local immune infiltrate but suggest a prominent role for clustered CD4-DC interactions in disease pathogenesis. Probably, the local inhibition of such interactions may constitute an efficient treatment modality.

Cutaneous T cell lymphomas (CTCL) are rare but aggressive cancers without effective treatments. While a subset of patients derive benefit from PD-1 blockade, there is a critically unmet need for predictive biomarkers of response. Herein, we perform CODEX multiplexed tissue imaging and RNA sequencing on 70 tumor regions from 14 advanced CTCL patients enrolled in a pembrolizumab clinical trial (NCT02243579). We find no differences in the frequencies of immune or tumor cells between responders and non-responders. Instead, we identify topographical differences between effector PD-1 + CD4 + T cells, tumor cells, and immunosuppressive Tregs, from which we derive a spatial biomarker, termed the SpatialScore, that correlates strongly with pembrolizumab response in CTCL. The SpatialScore coincides with differences in the functional immune state of the tumor microenvironment, T cell function, and tumor cell-specific chemokine recruitment and is validated using a simplified, clinically accessible tissue imaging platform. Collectively, these results provide a paradigm for investigating the spatial balance of effector and suppressive T cell activity and broadly leveraging this biomarker approach to inform the clinical use of immunotherapies., (© 2021. The Author(s).)

Background: Hypopigmented mycosis fungoides is a rare variant of mycosis fungoides that may mimic many benign inflammatory hypopigmented dermatoses, and as yet there is no identified marker to differentiate between them., Aim: The aim of this study was to study the expression of thymocyte selection-associated high-mobility group box (TOX) in hypopigmented mycosis fungoides and one of its inflammatory mimickers (early active vitiligo) to assess its potential as a differentiating diagnostic marker., Methods: A case-control study was done using immunohistochemical analysis of TOX expression in 15 patients with hypopigmented mycosis fungoides and 15 patients with early active vitiligo. Immunohistochemical analysis was done via a semi-quantitative method and an image analysis method., Results: Hypopigmented mycosis fungoides showed a statistically significant higher expression of TOX than early active vitiligo. The expression of TOX was positive in a majority of hypopigmented mycosis fungoides cases (14 cases, 93.3%), while only one case (6.7%) of vitiligo was weakly positive. TOX also displayed 93.3% sensitivity and specificity, with a cut-off value of 1.5., Limitations: This was a pilot study testing hypopigmented mycosis fungoides against only a single benign inflammatory mimicker (early vitiligo). Other benign mimickers were not included., Conclusion: Our findings showed that TOX expression can differentiate hypopigmented mycosis fungoides from early active vitiligo which is one of its benign inflammatory mimickers, with a high degree of sensitivity and specificity.

CD147, a transmembrane glycoprotein that belongs to the immunoglobulin superfamily, and cyclophilin A (CypA), one of the binding partners of CD147, are overexpressed in tumor cells and associated with the progression of several malignancies, including both solid and hematological malignancies. However, CD147 and CypA involvement in cutaneous T-cell lymphoma (CTCL) has not been reported. In this study, we examined CD147 and CypA expression and function using clinical samples of mycosis fungoides (MF) and Sézary syndrome (SS) and CTCL cell lines. CD147 and CypA were overexpressed by tumor cells of MF/SS, and CypA was also expressed by epidermal keratinocytes in MF/SS lesional skin. Serum CypA levels were increased and correlated with disease severity markers in MF/SS patients. Anti-CD147 antibody and/or anti-CypA antibody suppressed the proliferation of CTCL cell lines, both in vitro and in vivo, via downregulation of phosphorylated extracellular-regulated kinase 1/2 and Akt. These results suggest that CD147-CypA interactions can contribute to the proliferation of MF/SS tumor cells in both a autocrine and paracrine manner, and that the disruption of CD147-CypA interactions could be a new therapeutic strategy for the treatment of MF/SS.

Primary cutaneous T-cell lymphoma (CTCL) comprises a heterogeneous group of neoplasms with variable clinical behavior. Immunophenotypic switch (IS) is a phenomenon that occurs during lymphoma progression and is defined by an alteration in the immunophenotypic expression of a tumor with retention of its genotypic signature. This has been well-recognized in hematopoietic neoplasms; however, it has been rarely reported in CTCL and its clinical implications are not well understood. We present the clinical, histopathologic, immunophenotypic, and genetic findings of three cases of CTCL that demonstrated IS post treatment with variable outcomes. We add our cases to the small number previously reported to increase awareness of this phenomenon and its diagnostic challenge., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Mycosis fungoides (MF) is the most prevalent type of skin lymphoma. In its early stages, it has a favorable prognosis. However, in its late stages, it is associated with an increased risk of mortality. This systematic review aimed to identify the transcriptomic changes involved in MF pathogenesis and progression. A literature search was conducted using the database PubMed, followed by the extraction of 2245 genes which were further filtered to 150 recurrent genes that appeared in two or more publications. Categorization of these genes identified activated pathways involved in pathways such as cell cycle and proliferation, chromosomal instability, and DNA repair. We identified 15 genes implicated in MF progression, which were involved in cell proliferation, immune checkpoints, resistance to apoptosis, and immune response. In highlighting the discrepancies in the way MF transcriptomic data is obtained, further research can focus on not only unifying their approach but also focus on the 150 pertinent genes identified in this review.

Background: Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma (CTCL) that transforms from mature, skin-homing T cells and progresses during the early stages in the skin. The role of the skin microenvironment in MF development is unclear, but recent findings in a variety of cancers have highlighted the role of stromal fibroblasts in promoting or inhibiting tumorigenesis. Stromal fibroblasts are an important part of the cutaneous tumor microenvironment (TME) in MF. Here we describe studies into the interaction of TME-fibroblasts and malignant T cells to gain insight into their role in CTCL., Methods: Skin from normal (n = 3) and MF patients (n = 3) were analyzed for FAPα by immunohistochemistry. MyLa is a CTCL cell line that retains expression of biomarkers TWIST1 and TOX that are frequently detected in CTCL patients. MyLa cells were cultured in the presence or absence of normal or MF skin derived fibroblasts for 5 days, trypsinized to detached MyL a cells, and gene expression analyzed by RT-PCR for MF biomarkers (TWIST1 and TOX), Th1 markers (IFNG, TBX21), Th2 markers (GATA3, IL16), and proliferation marker (MKI67). Purified fibroblasts were assayed for VIM and ACTA2 gene expression. Cellular senescence assay was performed to assess senescence., Results: MF skin fibroblast showed increased expression of FAP-α with increasing stage compared to normal. Normal fibroblasts co-cultured with MyLa cells suppressed expression of TWIST1 (p < 0.0006), and TOX (p < 0.03), GATA3 (p < 0.02) and IL16 (p < 0.03), and increased expression of IFNG (p < 0.03) and TBX21 (p < 0.03) in MyLa cells. In contrast, MyLa cells cultured with MF fibroblasts retained high expression of TWIST1, TOX and GATA3. MF fibroblasts co-culture with MyLa cells increased expression of IL16 (p < 0.01) and IL4 (p < 0.02), and suppressed IFNG and TBX21 in MyLa cells. Furthermore, expression of MKI67 in MyLa cells was suppressed by normal fibroblasts compared to MF fibroblasts., Conclusion: Skin fibroblasts represent important components of the TME in MF. In co-culture model, normal and MF fibroblasts have differential influence on T-cell phenotype in modulating expression of Th1 cytokine and CTCL biomarker genes to reveal distinct roles with implications in MF progression.

Introduction: Mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma, can lead to disfiguring lesions, debilitating pruritus and frequent skin infections. This study assessed response to brentuximab vedotin in patients with MF in the phase III ALCANZA study., Methods: Baseline CD30 levels and large-cell transformation (LCT) status were centrally reviewed in patients with previously-treated CD30-positive MF using ≥2 skin biopsies obtained at screening; eligible patients required ≥1 biopsy with ≥10% CD30 expression. Patients were categorised as CD30 min  < 10% (≥1 biopsy with <10% CD30 expression), or CD30 min  ≥ 10% (all biopsies with ≥10% CD30 expression) and baseline LCT present or absent. Efficacy analyses were the proportion of patients with objective response lasting ≥4 months (ORR4) and progression-free survival (PFS)., Results: Clinical activity with brentuximab vedotin was observed across all CD30 expression levels in patients with ≥1 biopsy showing ≥10% CD30 expression. Superior ORR4 was observed with brentuximab vedotin versus physician's choice in patients: with CD30 min  < 10% (40.9% versus 9.5%), with CD30 min  ≥ 10% (57.1% versus 10.3%), with LCT (64.7% versus 17.6%) and without LCT (38.7% versus 6.5%). Brentuximab vedotin improved median PFS versus physician's choice in patients: with CD30 min  < 10% (16.7 versus 2.3 months), with CD30 min  ≥ 10% (15.5 versus 3.9 months), with LCT (15.5 versus 2.8 months) and without LCT (16.1 versus 3.5 months). Safety profiles were generally comparable across subgroups., Conclusion: These exploratory analyses demonstrated that brentuximab vedotin improved rates of ORR4 and PFS versus physician's choice in patients with CD30-positive MF and ≥1 biopsy showing ≥10% CD30 expression, regardless of LCT status., Clinical Trial Registration: Clinicaltrials.gov, NCT01578499., Competing Interests: Conflict of interest statement Y.H.K. reports advisory roles for Seagen and Takeda. H.M.P. reports advisory board for and grants or funds from Takeda. D.F. reports advisory roles for Kyowa Kirin. S.M.H. reports consulting fees from ADC Therapeutics, C4 Therapeutics, Celgene, Janssen, Kura Oncology, Kyowa Hakko Kirin, Myeloid Therapeutics, Seagen, Takeda, Verastem and Vividion Therapeutics, and research grants or funds from ADC Therapeutics, Aileron, Celgene, Daiichi Sankyo, Forty Seven, Inc., Kyowa Hakko Kirin, Millennium/Takeda, Portola Pharmaceuticals, Seagen, Trillium Therapeutics and Verastem. M.D. reports research funding from Takeda and Millennium for this study, Seagen for a physician IST, and institutional funding from Solenginex, miragene, Rhizen and Eisai. O.B. reports consulting fees from Novartis, BMS, Sanofi, Pierre, Fabre and MSD. J.A.S. reports speaker’s bureau, and consultancy/advisory roles for Takeda (Brazil). J.S. reports consulting fees from/Clinical Expert for Takeda. P.Q. reports advisory boards and speaker fee for Takeda, Kiowa, Therakos, Miragen, Helsinn-Recordati, Innate Pharma, 4SC and Actelion. P.L.Z. reports advisory roles for and honoraria from Merck, BMS, Servier, Takeda, TG Therapeutics, ADC Therapeutics, Abbvie, Incyte, Janssen, Gilead, Eusapharma, Roche, Debiopharm and Novartis. H.E. reports advisory roles for Abbvie and Genentech, honoraria from Abbvie, Genentech, Takeda and Pharmacyclics, grants or funds from Abbvie, Genentech, Pharmacyclics, Acerta, Celgene and Astrazeneca. L.C.P-B. reports advisory roles for and honoraria from Seagen. P.L.O-R. reports advisory roles for Takeda, Helsinn, 4SC, Actelion, Innate Pharma, Recordati Rare Diseases, Kyowa and miRagen, grants or funds from MEDA, and PLCG1 mutation patent. O.E.A. reports advisory roles for Trillium Therapeutics, Bioniz, Kyowa Kirin and Meivir, and research grants or funds from Actelion, Adaptive Biotechnology, Trillium Therapeutics, Pfizer and Kyowa Kirin. J.T. reports research funding from Takeda, Celgene, Roche, Beigene, Janssen and PCYC. M.W. reports honoraria from Takeda and Kyowa Kirin, and research grants or funds from Millennium. J.W. reports advisory roles for Roche, Celgene, Takeda, Janssen-Cilag, Servier, Amgen, BMS, Abbvie, Novartis and Gilead, honoraria from Roche, Celgene, Takeda, Janssen-Cilag, Servier, Amgen, Abbvie, Gilead and Novartis, grants or funds from Roche, GSK/Novartis, Takeda and Janssen-Cilag, and conference travel support from Roche. A.A.G. reports advisory roles for Seagen, Innate Pharma and StemLine Therapeutics, honoraria and grants or funds from StemLine Therapeutics, and consultancy fees from Innate Pharma and StemLine. L.B. reports employment for Zymeworks. M.C.P-W., J.L. and M.O. report employment for and ownership of stocks/shares from Seagen. V.B. reports employment for Takeda Pharmaceuticals. M.L. reports employment for and ownership of stocks/shares from Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd. W.L.T. reports employment for and ownership of stocks/shares from Takeda Pharmaceuticals. R.D. reports intermittent, project focused consulting and/or advisory relationships with Novartis, Merck Sharp & Dhome (MSD), Bristol-Myers Squibb (BMS), Roche, Amgen, Takeda, Pierre Fabre, Sun Pharma, Sanofi, Catalym, Second Genome, Regeneron and Alligator. S.W., R.S., P.W., K.T., and M.M. have no conflicts of interest to disclose., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mycosis fungoides (MF) is the most common primary cutaneous T-cell lymphoma. While initially restricted to the skin, malignant cells can appear in blood, bone marrow and secondary lymphoid organs in later disease stages. However, only little is known about phenotypic and functional properties of malignant T cells in relationship to tissue environments over the course of disease progression. We thus profiled the tumor micromilieu in skin, blood and lymph node in a patient with advanced MF using single-cell RNA sequencing combined with V-D-J T-cell receptor sequencing. In skin, we identified clonally expanded T-cells with characteristic features of tissue-resident memory T-cells (T RM , CD69 + CD27 - NR4A1 + RGS1 + AHR + ). In blood and lymph node, the malignant clones displayed a transcriptional program reminiscent of a more central memory-like phenotype ( KLF2 + TCF7 + S1PR1 + SELL + CCR7 + ), while retaining tissue-homing receptors (CLA , CCR10 ). The skin tumor microenvironment contained potentially tumor-permissive myeloid cells producing regulatory ( IDO1 ) and Th2-associated mediators ( CCL13, CCL17, CCL22 ). Given their expression of PVR, TNFRSF14 and CD80/CD86 , they might be under direct control by TIGIT + CTLA4 + CSF2 + TNFSF14 + tumor cells. In sum, this study highlights the adaptive phenotypic and functional plasticity of MF tumor cell clones. Thus, the T RM -like phenotype enables long-term skin residence of MF cells. Their switch to a T CM -like phenotype with persistent skin homing molecule expression in the circulation might explain the multi-focal nature of MF., Competing Interests: CJ is an employee of the Medical University of Vienna, and has received personal fees from AbbVie, Almirall, Amgen, Eli Lilly, Janssen, LEO Pharma, Mallinckrodt/Therakos, Pfizer, Novartis, Sandoz, Takeda, and UCB. CJ is an investigator for Eli Lilly and Company, Novartis and 4SC (grant paid to her institution). PB is an employee of the Medical University of Vienna, and has received personal fees from LEO Pharma, Pfizer, Sanofi Genzyme, Eli Lilly, Novartis, Celgene, UCB Pharma, Biotest, Boehringer Ingelheim, AbbVie, Amgen and Arena Pharmaceuticals. PB is an investigator for Novartis (grant paid to his institution). WB is an employee of the Medical University of Vienna and has received personal fees from Takeda, Abbvie, GSK/ViiV and Gilead. SP has received personal fees from Takeda. MM has received personal fees (speaker honoraria) from Siemens and Bristol Myers Squibb. WW is an employee of the Medical University of Vienna and has received personal fees from LEO Pharma, Pfizer, Sanofi Genzyme, Eli Lilly, Novartis, Boehringer Ingelheim, AbbVie, and Janssen. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Rindler, Bauer, Jonak, Wielscher, Shaw, Rojahn, Thaler, Porkert, Simonitsch-Klupp, Weninger, Mayerhoefer, Farlik and Brunner.)

Background: The surface protein CD30 is a therapeutic target of monoclonal antibody therapy. Knowledge of the frequency of CD30 expression and its prognostic relevance is therefore interesting, not only in lymphoproliferative disorders (LPD) but also in solid tumors of the skin., Methods: A review was completed in PubMed for all published reports of CD30 expression in cutaneous lymphomas, mastocytosis, epithelial tumors and sarcomas from 1982 to April 2019. Only accessible articles in English and German were considered. Entities with an expected CD30 expression, such as CD30-positive LPD, were not evaluated., Results: The electronic research identified 1091 articles and a further 34 articles were obtained from manual bibliographic reference. Overall 91 articles were included that examined CD30 expression in various entities of cutaneous neoplasms and matched the inclusion criteria., Conclusion: Apart from cutaneous CD30-positive LPD, the best-studied group for CD30 expression was mycosis fungoides (MF). CD30 positivity was found in 32% of classical (patch and plaque stage) and in 59.4% cases of transformed MF. CD30 was also frequently expressed in cutaneous mastocytosis (96.5%). In solid tumors, some single reports describe CD30 expression by tumor cells, but CD30-reactive lymphocytes were frequently observed in the tumor microenvironment (TME), especially in keratoacanthoma (KA)., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: Mycosis fungoides (MF) is the most common T-cell lymphoma, with indolent biologic behavior in the early stage and features of invasive in the tumor stage. The diagnosis of MF is still ambiguous and difficult. We focused on the proteomic profiling change in the pathogenesis of early MF and identified candidate biomarkers for early diagnosis., Methods: We collected peripheral blood samples of MF patients and healthy individuals (HI) performed proteomic profiling analysis using isobaric tags for relative and absolute quantification (iTRAQ) platform. Differently expressed proteins (DEPs) were filtered, and involved biological functions were analyzed through Gene Ontology (GO) and Ingenuity Pathway Analysis (IPA) software., Results: We identified 78 DEPs including fifty proteins were upregulated and 28 proteins were downregulated in the MF group with HI as a control. Total DEPs were analyzed according to the biological regulation and metabolic process through GO analysis. The pathways of LXR/RXR activation and FXR/RXR activation were significantly activated, in which APOH, CLU, and ITIH4 were involved. The top annotated disease and function network was (Cancer, Organismal Injury and Abnormalities, Reproductive System Disease), with a key node CLU. These DEPs were involved in cancer, including thyroid carcinoma, head and neck carcinoma, and cancer of secretory structure, in which CLU, GNAS, and PKM played an indirect role in the occurrence and development of cancer. Relevant causal network was IL12 (family), which is related to GNAS, PKM, and other DEPs., Conclusion: Proteomic profiling of early-stage MF provided candidate protein biomarkers such as CLU, GNAS, and PKM, which benefit the early diagnosis and understanding of the mechanism of MF development. Besides, lipid metabolism may be one of the pathogenesis of MF, and IL12 was a potential marker for the diagnosis and treatment of early MF., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Mengyan Zhu et al.)

Background: Systemic chemotherapy is often the last resort of advanced cutaneous T-cell lymphoma (CTCL). Tumor recurrence and adverse effects of systemic chemotherapy are the main limitations., Objective: We aim to investigate the metabolic alterations in tumor cells after CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone) chemotherapy., Methods and Results: In advanced CTCL, CHOP chemotherapy has no survival benefit and the duration of response is significantly inferior to other canonical treatments. HIF-1α is significantly elevated in lesions of advanced MF patients as well as tumor cell line Hut78 and tumor xenograft mice model. CHOP therapy also increased glycolytic activities in a HIF-1α-dependent manner. In CTCL xenograft tumor mice model, lesional cells showed a significant increase in IL-17F after chemotherapy, shifting toward a Th17 phenotype, which process is also regulated by HIF-1α. Echinomycin, HIF-1α inhibitor, was co-administered in xenograft tumor mouse models with CHOP and showed a significant reduction in tumor growth., Conclusion: CHOP chemotherapy promotes glycolysis and IL-17 pathways in a HIF-1α-dependent fashion. Furthermore, HIF-1α blockade is promising as an accompanying agent in systemic chemotherapy for patients with advanced CTCL., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Sézary syndrome (SS) is an aggressive form of cutaneous T-cell lymphoma (CTCL) characterized by the presence of circulating malignant CD4+ T cells (Sézary cells) with many complex changes in the genome, transcriptome and epigenome. Epigenetic dysregulation seems to have an important role in the development and progression of SS as it was shown that SS cells are characterized by widespread changes in DNA methylation. In this study, we show that the transmembrane protein coding gene TMEM244 is ectopically expressed in all SS patients and SS-derived cell lines and, to a lower extent, in mycosis fungoides and in a fraction of T-cell lymphomas, but not in B-cell malignancies and mononuclear cells of healthy individuals. We show that in patient samples and in the T-cell lines TMEM244 expression is negatively correlated with the methylation level of its promoter. Furthermore, we demonstrate that TMEM244 expression can be activated in vitro by the CRISPR-dCas9-induced specific demethylation of TMEM244 promoter region. Since both, TMEM244 expression and its promoter demethylation, are not detected in normal lymphoid cells, they can be potentially used as markers in Sézary syndrome and some other T-cell lymphomas., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

In many malignancies, dysregulation of the Notch pathways, composed of 4 Notch receptors (Notch1-4) and 5 Notch ligands (Jagged1-2, Delta-like ligand-1, 3-4), is associated with their development. In mycosis fungoides, interaction between Notch1 and Jagged1 is known to activate the Notch pathways and promote the proliferation of tumour cells. However, the involvement of other Notch ligands has not been reported. This study investigated the roles of Delta-like ligand 4 in mycosis fungoides. Delta-like ligand 4 mRNA levels in lesional skin of patients with mycosis fungoides were significantly elevated compared with those of normal controls, and correlated with disease-specific mortality. Immunohistochemical staining demonstrated prominent expression of Delta-like ligand 4 on vascular endothelial cells and tumour cells in mycosis fungoides lesional skin. In addition, Delta-like ligand 4 augmented the proliferation of cutaneous T-cell lym-phoma cell lines. These results suggest that enhanced Delta-like ligand 4 expression may contribute directly to the progression of mycosis fungoides through proliferating tumour cells.

Purpose: To assess the efficacy of pembrolizumab in patients with advanced relapsed or refractory mycosis fungoides (MF) or Sézary syndrome (SS)., Patients and Methods: CITN-10 is a single-arm, multicenter phase II trial of 24 patients with advanced MF or SS. Patients were treated with pembrolizumab 2 mg/kg every 3 weeks for up to 24 months. The primary end point was overall response rate by consensus global response criteria., Results: Patients had advanced-stage disease (23 of 24 with stage IIB to IV MF/SS) and were heavily pretreated with a median of four prior systemic therapies. The overall response rate was 38% with two complete responses and seven partial responses. Of the nine responding patients, six had 90% or more improvement in skin disease by modified Severity Weighted Assessment Tool, and eight had ongoing responses at last follow-up. The median duration of response was not reached, with a median response follow-up time of 58 weeks. Immune-related adverse events led to treatment discontinuation in four patients. A transient worsening of erythroderma and pruritus occurred in 53% of patients with SS. This cutaneous flare reaction did not result in treatment discontinuation for any patient. The flare reaction correlated with high PD-1 expression on Sézary cells but did not associate with subsequent clinical responses or lack of response. Treatment responses did not correlate with expression of PD-L1, total mutation burden, or an interferon-γ gene expression signature., Conclusion: Pembrolizumab demonstrated significant antitumor activity with durable responses and a favorable safety profile in patients with advanced MF/SS.

Mycosis Fungoides (MF) is the most common subtype of cutaneous T-cell lymphomas (CTCL). Shank-associated RH domain-interacting protein (SHARPIN) participates in the initiation and development of multiple tumors. However, the clinical significance of SHARPIN in MF hasn't been investigated. The c-Jun N-terminal kinases (JNKs) pathway is a member of mitogen-activated protein kinases (MAPKs). Its dysregulation is observed in various tumors including CTCL, whereas the roles of JNKs pathway in MF remain largely unknown, the relationship between SHARPIN and JNKs pathway remains elusive. Herein, we showed that upregulated expression of SHARPIN was related to poor prognosis of MF patients. In vitro experiments found increased SHARPIN expression and activation of JNKs pathway in MF cell line MyLa2059. SHARPIN induced transforming growth factor β activated kinase-1 (TAK1) transcription, which is an upstream kinase of JNKs, NF-κB and p38 pathway, leading to activation of JNKs and NF-κB pathway. SHARPIN also promoted p38 signalling independent of TAK1 expression, by which overexpression of SHARPIN induced cell proliferation, inhibited apoptosis, enhanced migration and invasion of MyLa2059. Our work provided direct evidences for effects of SHARPIN on JNKs and NF-κB pathway, and the contributing roles of JNKs, NF-κB and p38 pathway regulated by SHARPIN in the development of MF., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Mycosis Fungoides (MF) is the most common type of cutaneous T-cell lymphomas. Early stage patients are treated with topical therapies and have normal life expectancy whereas patients with advanced disease encounter frequent relapses and have a five-year survival rate that does not exceed 15%. The aim of the present study was to characterize the expression of microRNA-16 (miR-16) and microRNA-93 (miR-93) in early and advanced cases of MF in relation to the clinicopathological parameters. Ten skin biopsies of early and advanced MF were investigated for the expression of miR-16 and miR-93 using RT-PCR. Immunohistochemical expression of apoptosis markers (BCL-2 and Survivin) were also investigated in the studied cases compared to normal skin and eczema biopsies. In the present study, BCL-2 and Survivin showed strong positive expression on neoplastic lymphocytes in all cases of MF regardless of their stage. We have also shown that miR-16 was significantly upregulated in advanced cases of MF compared to cases with early disease (p-value was less than 0.05). However, expression of miR-16 did not show any statistically significant correlation with age, gender, or expression of apoptotic markers. On the other hand, the expression of miR-93 showed significant downregulation in all lymphoma cases irrespective of their stage, compared to normal and eczema cases. Our results suggest that upregulation of miR-16 could be used to predict an aggressive course of the disease. We also suggest that miR-93 downregulation could serve as possible tool for establishing early diagnosis in early challenging cases. Our findings also provide consistent evidence that the anti-apoptotic molecules may play an important role in the pathogenesis of this type of cutaneous lymphomas and promote the idea that their inhibition could be an interesting novel therapeutic strategy in the treatment of MF., Competing Interests: The authors have declared that no competing interests exist.

Background: Mycosis fungoides (MF) is characterized by epidermotropic atypical lymphocytes in the absence of spongiosis. However, we describe an unusual presentation of MF with spongiosis, mimicking benign inflammatory dermatoses and highlight the importance of pathologic interpretation for diagnostic confirmation., Methods: A cross-sectional study of consecutive patients diagnosed with MF with spongiosis was conducted. The clinical, histopathologic, immunophenotypic, and molecular genetic features of cases were reviewed., Results: We identified nine cases of MF (age range 34-82 years; mean 75 years), with an initial diagnosis of dermatitis (6/9), psoriasis (4/9), or other inflammatory dermatoses (2/9). Pruritus, pain, and blisters were common clinical manifestations. The most common areas of involvement were the extremities (8/9). Epidermotropism with spongiosis was a central histopathological feature in all cases., Conclusion: These cases highlight prominent spongiosis in MF and overlap with common benign inflammatory dermatoses. We present these cases to show the diagnostic pitfalls associated with spongiotic presentations of MF. Dermatitis, psoriasis, and other inflammatory skin conditions not responsive to standard therapy warrant further work-up including biopsy to rule out MF. Multiple skin biopsies and review by a dermatopathologist with expertise in the diagnosis of cutaneous lymphoma is highly recommended., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Introduction: Mycosis fungoides (MF) with large cell transformation (LCT) is an advanced stage of cutaneous lymphoma with a poor prognosis. Identification of LCT is critical and especially challenging when the number of large abnormal lymphocytes is near but below 25%. We propose that Ki-67 and p53 may be useful in making this diagnosis., Methods: We identified 17 patients with advanced stage (T3 or T4) MF without LCT and 38 patients with a biopsy-confirmed new diagnosis of MF with LCT treated at our institution's cutaneous lymphoma clinic from 2012 to 2016. Seventeen patients underwent 22 biopsies with advanced stage MF (control), and 38 patients with 46 biopsies of MF with LCT were included in this study., Results: The MF cohort had an average CD30 expression of 4%, while the MF-LCT cohort had an average CD30 expression of 22% (P < 0.05). The MF cohort had an average Ki-67 staining of 13%, while the MF-LCT group had an average Ki-67 staining of 57% (P < 0.05). Forty-seven percent of the MF-LCT group was positive for p53; on the other hand, none of the MF control group showed increased p53 expression (P < 0.05)., Discussion: While CD30 shows some value in delineating large cell transformation, Ki-67 and p53 appear to be useful immunohistochemical markers in the diagnosis of LCT., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Progranulin (PGRN) is a multi-functional protein known to be involved in diverse biological processes, including tumourigenesis, anti-inflammation, and anti-infection. PGRN expression in sera or tissues is elevated in a variety of malignancies and is associated with poor prognosis. However, it remains to be determined whether PGRN is involved in Mycosis fungoides (MF). To investigate the roles of PGRN in MF. Serum PGRN levels were measured in patients with MF and normal controls by enzyme-linked immunosorbent assay. PGRN expression in MF and normal skin was examined by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. Moreover, we analysed correlations between the expression levels of PGRN and antimicrobial peptides in lesional skin. PGRN levels were significantly lower in sera of MF patients than those of normal controls. PGRN mRNA levels in lesional skin of MF were also significantly decreased. Immunohistochemical staining revealed that PGRN was expressed in epidermal keratinocytes of normal controls, however, PGRN expression in epidermal keratinocytes was also weaker in MF skin. Furthermore, significant inverse correlations were identified between PGRN and antimicrobial peptide mRNA expression. These results suggest that low PGRN expression may contribute to the frequent occurrence of skin infections in patients with MF.

Primary cutaneous T-cell lymphoma (CTCL) comprises the second most common group of extra-nodal non-Hodgkin's lymphoma. They represent incurable primary extra-nodal lymphomas of major T cells, uniformly present in the skin with 1%-2% risk of systemic dissemination in mycosis fungoides (MF), which represents the most common subtype of CTCL. In general, long-term antigen stimulation is thought, through key cytokine signalling pathways, to induce an inflammatory response with T-cell proliferation, leading to a clonal malignant T cell with continuous expansion. However, in recent years, using data harvested from high-throughput transcriptional profiling, substantial advances in the understanding of the molecular pathogenesis were made to understand the complex pathogenesis of CTCL. In this review, the actual data are summarised., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

A 52-year-old woman diagnosed with mycosis fungoides was referred for F-FDG PET/CT before treatment for the evaluation of disease severity. The patient also underwent Ga-pentixafor PET/CT for further evaluation. FDG uptake was observed in cervical, axillary, and pelvic lymph nodes and multiple widespread skin lesions throughout the body, suggestive of extensive involvement of mycosis fungoides. All lesions were visually identifiable with high target-to-background ratio on Ga-pentixafor PET/CT which demonstrated marked CXCR4 expression in all lesions that were detected using F-FDG PET/CT.

Differentiating early mycosis fungoides (MF) from inflammatory dermatitis is a challenge. We compare the differential expression profile of early-stage MF samples and benign inflammatory dermatoses using microRNA (miRNA) arrays. 114 miRNAs were found to be dysregulated between these entities. The seven most differentially expressed miRNAs between these two conditions were further analyzed using RT-PCR in two series comprising 38 samples of early MFs and 18 samples of inflammatory dermatitis. A series of 51 paraffin-embedded samples belonging to paired stages of 16 MF patients was also analyzed. MiRNAs 26a, 222, 181a and 146a were differentially expressed between tumoral and inflammatory conditions. Two of these miRNAs (miRNA-181a and miRNA-146a) were significantly deregulated between early and advanced MF stages. Bioinformatic analysis showed FOXP3 expression to be regulated by these miRNAs. Immunohistochemistry revealed the level of FOXP3 expression to be lower in tumoral MFs than in plaque lesions in paraffin-embedded tissue. A functional study confirmed that both miRNAs diminished FOXP3 expression when overexpressed in CTCL cells. The data presented here suggest that the analysis of a restricted number of miRNAs (26a, 222, 181a and 146a) could be sufficient to differentiate tumoral from reactive conditions. Moreover, these miRNAs seem to be involved in MF progression., Competing Interests: The authors have declared that no competing interests exist.

Background: Mycosis fungoides (MF) is the major subtype of cutaneous T-cell lymphomas (CTCL). It usually has a prolonged indolent clinical course with a minority of cases acquiring a more aggressive biological profile and resistance to conventional therapies, partially attributed to the persistent activation of nuclear factor-kappa B (NF-κB) pathway. In the last decade, several papers suggested an important role for the FK506-binding protein 51 (FKBP51), an immunophilin initially cloned in lymphocytes, in the control of NF-κB pathway in different types of human malignancies., Objectives: We aimed to investigate the possible value of FKBP51 expression as a new reliable marker of outcome in patients with MF., Methods: We assessed by immunohistochemistry (IHC) FKBP51 expression in 44 patients with MF, representative of different stages of the disease. Immunohistochemical results were subsequently confirmed at mRNA level with quantitative PCR (qPCR) in a subset of enrolled patients. In addition, IHC and qPCR served to study the expression of some NF-κB-target genes, including the tumour necrosis factor receptor-associated factor 2 (TRAF2)., Results: Our results show that FKBP51 was expressed in all evaluated cases, with the highest level of expression characterizing MFs with the worst prognosis. Moreover, a significant correlation subsisted between FKBP51 and TRAF2 IHC expression scores., Conclusions: We hypothesize a role for FKBP51 as a prognostic marker for MF and suggest an involvement of this immunophilin in deregulated NF-κB pathway of this CTCL., (© 2017 European Academy of Dermatology and Venereology.)