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Altered miRNA expressions are assigned pathogenic properties in several cancers including mycosis fungoides and could play a role in the early onset of the disease. The aim of this study was to examine disease-specific miRNA expression in early-stage mycosis fungoides patch and plaque lesions. A quantitative real-time PCR platform of 384 human miRNAs was used to study miRNA expression in 154 diagnostic mycosis fungoides biopsies. A total of 110 miRNAs were significantly differentially expressed (>2-fold, p < 0.05) between plaque lesions and healthy controls, and 90 miRNAs (>2-fold, p < 0.05) differed between patch lesions and healthy controls. Moreover, 13 miRNAs differed in expression between patch and plaque lesions. Early-stage mycosis fungoides exhibited miRNA features that overlapped with those of psoriasis. However, 39 miRNAs, including miR-142-3p, miR-150 and miR-146b, were specific to mycosis fungoides. In conclusion, early-stage mycosis fungoides expresses a distinct miRNA profile, indicating that miRNAs could play a role in the early development of mycosis fungoides. [ABSTRACT FROM AUTHOR]

Background: Several cancers, including mycosis fungoides (MF), have reported dysregulation of miR‐195‐5p. miR‐195‐5p plays a role in cell cycle regulation in several malignant diseases. Objectives: This study aimed to investigate: (a) the expression level of miR‐195‐5p in lesional MF skin biopsies and (b) the potential regulatory roles of miR‐195‐5p in MF. Methods: Quantitative real‐time polymerase chain reaction (RT‐qPCR) was used to determine miR‐195‐5p expression in MF skin biopsies and cell lines. The effect of miR‐195‐5p and ADP‐ribosylation factor‐like protein 2 (ARL2) on cell cycle and apoptosis was measured by flow cytometry assays. Changes in ARL2 expression were determined by RT‐qPCR and Western blotting (WB). Results: We found lower expression levels of miR‐195‐5p in lesional skin from MF patients compared with non‐lesional MF skin and skin from healthy volunteers. Additionally, miR‐195‐5p showed lower expression levels in the skin from patients with disease progression compared with patients with stable disease. In vitro studies showed that overexpression of miR‐195‐5p induced a cell cycle arrest in G0G1. Using microarray analysis, we identified several genes that were regulated after miR‐195‐5p overexpression. The most downregulated gene after miR‐195‐5p mimic transfection was ARL2. RT‐qPCR and WB analyses confirmed downregulation of ARL2 following transfection with miR‐195‐5p mimic. Lastly, transfection with siRNA against ARL2 also induced a G0G1 arrest. Conclusion: Upregulation of miR‐195‐5p in MF inhibits cycle arrest by downregulation of ARL2. miR‐195‐5p may thus function as a tumor suppressor in MF and low miR‐195‐5p expression in lesional MF skin may promote disease progression. [ABSTRACT FROM AUTHOR]

Mycosis fungoides (MF) is the most frequent form of cutaneous T-cell lymphoma. The disease often takes an indolent course, but in approximately one-third of the patients, the disease progresses to an aggressive malignancy with a poor prognosis. At the time of diagnosis, it is impossible to predict which patients develop severe disease and are in need of aggressive treatment. Accordingly, we investigated the prognostic potential of microRNAs (miRNAs) at the time of diagnosis in MF. Using a quantitative reverse transcription polymerase chain reaction platform, we analyzed miRNA expression in diagnostic skin biopsies from 154 Danish patients with early-stage MF. The patients were subdivided into a discovery cohort (n = 82) and an independent validation cohort (n = 72). The miRNA classifier was built using a LASSO (least absolute shrinkage and selection operator) Cox regression to predict progression-free survival (PFS). We developed a 3-miRNA classifier, based on miR-106b-5p, miR-148a-3p, and miR-338-3p, which successfully separated patients into high-risk and low-risk groups of disease progression. PFS was significantly different between these groups in both the discovery cohort and the validation cohort. The classifier was stronger than existing clinical prognostic factors and remained a strong independent prognostic tool after stratification and adjustment for these factors. Importantly, patients in the high-risk group had a significantly reduced overall survival. The 3-miRNA classifier is an effective tool to predict disease progression of early-stage MF at the time of diagnosis. The classifier adds significant prognostic value to existing clinical prognostic factors and may facilitate more individualized treatment of these patients. [ABSTRACT FROM AUTHOR]