CD39 is expressed by a wide range of cutaneous T-cell lymphomas.

CD39, an ectoenzyme in the immunosuppressive CD39/CD73/adenosine pathway, known to promote solid tumour outgrowth and spreading, was investigated in both skin and blood compartments of cutaneous T cell lymphomas. CD39 was overexpressed by peripheral blood T-cells in Sezary syndrome and mycosis fungoides, and in skin-infiltrating lymphocytes of Sezary syndrome, mycosis fungoides, subcutaneous panniculitis-like T-cell lymphoma and primary cutaneous CD30-positive lymphoproliferation. Our study emphasizes the interest in using CD39/CD73/adenosine pathway blocking agents for cutaneous T cell lymphomas treatment.

Inactivation of kindlin-3 increases human melanoma aggressiveness through the collagen-activated tyrosine kinase receptor DDR1.

The role of the focal adhesion protein kindlin-3 as a tumor suppressor and its interaction mechanisms with extracellular matrix constitute a major field of investigation to better decipher tumor progression. Besides the well-described role of kindlin-3 in integrin activation, evidence regarding modulatory functions between melanoma cells and tumor microenvironment are lacking and data are needed to understand mechanisms driven by kindlin-3 inactivation. Here, we show that kindlin-3 inactivation through knockdown or somatic mutations increases BRAFV600mut melanoma cells oncogenic properties via collagen-related signaling by decreasing cell adhesion and enhancing proliferation and migration in vitro, and by promoting tumor growth in mice. Mechanistic analysis reveals that kindlin-3 interacts with the collagen-activated tyrosine kinase receptor DDR1 (Discoidin domain receptor 1) modulating its expression and its interaction with ß1-integrin. Kindlin-3 knockdown or mutational inactivation disrupt DDR1/ß1-integrin complex in vitro and in vivo and its loss improves the anti-proliferative effect of DDR1 inhibition. In agreement, kindlin-3 downregulation is associated with DDR1 over-expression in situ and linked to worse melanoma prognosis. Our study reveals a unique mechanism of action of kindlin-3 in the regulation of tumorigenesis mediated by the collagen-activated tyrosine kinase receptor DDR1 thus paving the way for innovative therapeutic targeting approaches in melanoma.

PROM2 overexpression induces metastatic potential through epithelial-to-mesenchymal transition and ferroptosis resistance in human cancers.

INTRODUCTION: Despite considerable therapeutic advances in the last 20 years, metastatic cancers remain a major cause of death. We previously identified prominin-2 (PROM2) as a biomarker predictive of distant metastases and decreased survival, thus providing a promising bio-target. In this translational study, we set out to decipher the biological roles of PROM2 during the metastatic process and resistance to cell death, in particular for metastatic melanoma. METHODS AND RESULTS: Methods and results: We demonstrated that PROM2 overexpression was closely linked to an increased metastatic potential through the increase of epithelial-to-mesenchymal transition (EMT) marker expression and ferroptosis resistance. This was also found in renal cell carcinoma and triple negative breast cancer patient-derived xenograft models. Using an oligonucleotide anti-sense anti-PROM2, we efficaciously decreased PROM2 expression and prevented metastases in melanoma xenografts. We also demonstrated that PROM2 was implicated in an aggravation loop, contributing to increase the metastatic burden both in murine metastatic models and in patients with metastatic melanoma. The metastatic burden is closely linked to PROM2 expression through the expression of EMT markers and ferroptosis cell death resistance in a deterioration loop. CONCLUSION: Our results open the way for further studies using PROM2 as a bio-target in resort situations in human metastatic melanoma and also in other cancer types.

From Histiocytoid Sweet Syndrome to Myelodysplasia Cutis: History and Perspectives.

In 2005, a new histologic variant of Sweet syndrome (SS) has been described and termed histiocytoid SS (HSS). Clinically, patients had a typical SS, but on skin biopsy, the infiltrates were composed of immature nonblast myeloid cells. Nearly 50% of patients with HSS have myelodysplastic syndrome (MDS). HSS may be the first manifestation leading to the diagnosis of MDS. In 2015, a new category of myeloid dermatosis has been proposed, called myelodysplasia cutis, describing the specific skin infiltration by myelodysplastic cells in patients with MDS.

A Sub-Group of Kidney-Transplant Recipients with Highly Aggressive Squamous Cell Carcinoma Expressing Phosphorylated Serine392p53.

Cutaneous squamous cell carcinomas in kidney-transplant recipients are frequent, with an increasing incidence linked to long immunosuppression durations and exposure to ultraviolet radiation. p53 is at the cornerstone of ultraviolet-induced DNA damage, but the role of p53 post-translational modifications in this context is not yet deciphered. Here, we investigated the phosphorylation status of p53 at Serine 392 in 25 cutaneous squamous cell carcinomas in kidney-transplant recipients, compared with 22 non-transplanted patients. Cutaneous squamous cell carcinomas in transplanted patients occurred after a median period of 19 years of immunosuppression, with a median number of 15 cutaneous squamous cell carcinomas and more aggressive histological and clinical characteristics. There was no significant difference between Ki67, p53, and pSer392p53 expression in the two groups. Using principal component analysis, we identified a cluster of exclusively transplanted patients with a median of 23 years of immunosuppression duration, significantly more aggressive biological characteristics, and higher pSer392p53 expression. pSer392p53 was expressed in the whole tumor, suggesting an early carcinogenic event in the course of prolonged immunosuppression. This high, diffuse pSer392p53 expression, corresponding to a high level of DNA damage, might be useful to identify aggressive cutaneous squamous cell carcinomas in kidney-transplant recipients to treat them more aggressively.

SOX10-Internal Tandem Duplications and PLAG1 or HMGA2 Fusions Segregate Eccrine-Type and Apocrine-Type Cutaneous Mixed Tumors.

Cutaneous mixed tumors exhibit a wide morphologic diversity and are currently classified into apocrine and eccrine types based on their morphologic differentiation. Some cases of apocrine-type cutaneous mixed tumors (ACMT), namely, hyaline cell-rich apocrine cutaneous mixed tumors (HCR-ACMT) show a prominent or exclusive plasmacytoid myoepithelial component. Although recurrent fusions of PLAG1 have been observed in ACMT, the oncogenic driver of eccrine-type cutaneous mixed tumors (ECMT) is still unknown. The aim of the study was to provide a comprehensive morphologic, immunohistochemical, and molecular characterization of these tumors. Forty-one cases were included in this study: 28 cases of ACMT/HCR-ACMT and 13 cases of ECMT. After morphologic and immunohistochemical characterization, all specimens were analyzed by RNA sequencing. By immunohistochemistry, all cases showed expression of SOX10, but only ACMT/HCR-ACMT showed expression of PLAG1 and HMGA2. RNA sequencing confirmed the presence of recurrent fusion of PLAG1 or HMGA2 in all cases of ACMT/HCR-ACMT, with a perfect correlation with PLAG1/HMGA2 immunohistochemical status, and revealed internal tandem duplications of SOX10 (SOX10-ITD) in all cases of ECMT. Although TRPS1::PLAG1 was the most frequent fusion, HMGA2::WIF1 and HMGA2::NFIB were detected in ACMT cases. Clustering analysis based on gene expression profiling of 110 tumors, including numerous histotypes, showed that ECMT formed a distinct group compared with all other tumors. ACMT, HCR-ACMT, and salivary gland pleomorphic adenoma clustered together, whereas myoepithelioma with fusions of EWSR1, FUS, PBX1, PBX3, POU5F1, and KLF17 formed another cluster. Follow-up showed no evidence of disease in 23 cases across all 3 tumor types. In conclusion, our study demonstrated for the first time SOX10-ITD in ECMT and HMGA2 fusions in ACMT and further refined the prevalence of PLAG1 fusions in ACMT. Clustering analyses revealed the transcriptomic distance between these different tumors, especially in the heterogenous group of myoepitheliomas.

Gene fusions in poroma, porocarcinoma and related adnexal skin tumours: An update.

Poroma is a benign sweat gland tumour showing morphological features recapitulating the superficial portion of the eccrine sweat coil. A subset of poromas may transform into porocarcinoma, its malignant counterpart. Poroma and porocarcinoma are characterised by recurrent gene fusions involving YAP1, a transcriptional co-activator, which is controlled by the Hippo signalling pathway. The fusion genes frequently involve MAML2 and NUTM1, which are also rearranged in other cutaneous and extracutaneous neoplasms. We aimed to review the clinical, morphological and molecular features of this category of adnexal neoplasms with a special focus upon emerging differential diagnoses, and discuss how their systematic molecular characterisation may contribute to a standardisation of diagnosis, more accurate classification and, ultimately, refinement of their prognosis and therapeutic modalities.

Two cases of dupilumab-responsive Kimura disease.

Kimura disease (KD) is a rare, chronic angiolymphoproliferative inflammatory disease appearing to be mostly restricted to the skin and soft tissue. Cutaneous involvement of KD includes head and/or neck nodules showing suggestive histological features, frequently associated with an atopic dermatitis-like or prurigo-like presentation. KD is challenging to treat, with high rate of recurrence using current therapeutic strategies. Evidence for involvement of a T-helper type 2 (Th2) immune response in KD pathogenesis has been found in previous studies. Consequently, this study aimed to determine the efficacy and safety of dupilumab, a human monoclonal antibody that inhibits signalling of key Th2 cytokines, interleukin (IL)-4 and IL-13, within a single-centre cohort of patients with cutaneous KD. Two adults with a diagnosis of refractory (failure of at least one treatment line) cutaneous-restricted KD based on clinical, biological, histological, molecular and imaging findings received dupilumab for KD, and showed dramatic response with a good safety profile.

Paradoxical inflammatory blepharitis in a patient with Crohn's disease.

We report the case of a 15-year-old boy with severe inflammatory blepharitis who was being treated with a TNFα inhibitor for Crohn's disease (CD). This case shows the potential utility of a skin biopsy in distinguishing metastatic CD associated with granulomatous blepharitis from a paradoxical blepharitis induced by anti-TNFα. It also demonstrates that ustekinumab can be considered in patients with CD who cannot tolerate TNFα inhibitors because of cutaneous paradoxical reactions.