In recent years, knowledge about the wide spectrum of cutaneous T-cell lymphomas (CTCL) has broadened. Mycosis fungoides (MF) comprises about 50-70% of all primary cutaneous T-cell lymphomas (Willemze et al, 2019). Many CTCL are misdiagnosed due to clinical and histopathological similarity to other skin conditions (such as psoriasis vulgaris, atopic dermatitis and tinea corpora), low prevalence of disease and a lack of reliable tools for detection of these diseases, resulting in delayed diagnosis with years of discomfort and possibly a worse prognosis. Furthermore, standard treatment has never been proven curative, has many side effects and exacerbations are frequent. To date, the etiology of mycosis fungoides remains unknown and little research has been conducted into the mechanisms underlying its development and its response to treatment.~Mycosis fungoides lesions change over time and differ between patients, consisting of three morphologically different stages: patches (erythematosquamous maculae), plaques (erythematosquamous, elevated and occasionally infiltrated lesions) and tumors (with or without ulceration). Only a relatively small group of patients advances to tumor stage MF during their lifetime. Mycosis fungoides is diagnosed by correlating clinical appearance with histopathological analysis of an invasive skin punch biopsy. Additionally, often multiple biopsies are required after diagnosis, e.g. when a lesion is clinically advancing to a different stage or if lesion origin is ambiguous. Currently no other biomarkers besides skin punch biopsies markers are available for the diagnosis of MF, the evaluation of a MF lesion over time, and the monitoring of a potential treatment effect. To advance MF patient care and the development of novel treatments for MF objective, sensitive and reliable (preferably non-invasive) tools are desired.~Therefore, the objective of the current study is to evaluate disease-related characteristics and biomarkers, the intra- and inter-patient variability of biomarkers, to evaluate biomarkers for disease-monitoring following CL gel treatment and to investigate and monitor skin-related adverse events that might develop after CL gel application in MF patients. With this approach the investigators aim to detect novel biomarkers and to establish methodologies for the (non-)invasive monitoring of MF.~For this purpose, a multi-modal patient profiling approach with in-depth characterization of cutaneous T-cell lymphomas will be performed. A clinical study will be conducted investigating the biology of the disease compared to healthy volunteers (part A) and patients' response to intervention (part B). The former to characterize objectively measured disease characteristics and mechanisms underlying its development, the latter to monitor the biomarker response associated to a MF-CTCL treatment, in this case CL gel. The study focusses on cellular, molecular, biophysical, imaging and microbiome analyses in comparison to healthy controls and between lesional and non-lesional skin of MF patients.
Mycosis fungoides (MF) is an ultra-orphan disease of which the etiology remains unknown. MF is diagnosed by correlating clinical appearance with histopathological analysis of often multiple invasive skin punch biopsies. To move patient care and the development of novel treatments for MF forward, objective, sensitive and reliable tools that are preferably non-invasive are desired. Therefore, the objective of the current study is to phenotype the early stages of mycosis fungoides in detail and to assess the response of chlormethine (CL) gel monotherapy. With this approach the investigators aim to detect novel biomarkers and to establish methodologies for the (non-)invasive monitoring of MF.