Diagnostic microRNA profiling in cutaneous T-cell lymphoma (CTCL).

Cutaneous T-cell lymphomas (CTCLs) are the most frequent primary skin lymphomas. Nevertheless, diagnosis of early disease has proven difficult because of a clinical and histologic resemblance to benign inflammatory skin diseases. To address whether microRNA (miRNA) profiling can discriminate CTCL from benign inflammation, we studied miRNA expression levels in 198 patients with CTCL, peripheral T-cell lymphoma (PTL), and benign skin diseases (psoriasis and dermatitis). Using microarrays, we show that the most induced (miR-326, miR-663b, and miR-711) and repressed (miR-203 and miR-205) miRNAs distinguish CTCL from benign skin diseases with > 90% accuracy in a training set of 90 samples and a test set of 58 blinded samples. These miRNAs also distinguish malignant and benign lesions in an independent set of 50 patients with PTL and skin inflammation and in experimental human xenograft mouse models of psoriasis and CTCL. Quantitative (q)RT-PCR analysis of 103 patients with CTCL and benign skin disorders validates differential expression of 4 of the 5 miRNAs and confirms previous reports on miR-155 in CTCL. A qRT-PCR-based classifier consisting of miR-155, miR-203, and miR-205 distinguishes CTCL from benign disorders with high specificity and sensitivity, and with a classification accuracy of 95%, indicating that miRNAs have a high diagnostic potential in CTCL.

A novel xenograft model of cutaneous T-cell lymphoma.

Cutaneous T-cell lymphomas (CTCLs) are characterized by accumulation of malignant T cells in the skin. Early disease resembles benign skin disorders but during disease progression cutaneous tumors develop, and eventually the malignant T cells can spread to lymph nodes and internal organs. However, because of the lack of suitable animal models, little is known about the mechanisms driving CTCL development and progression in vivo. Here, we describe a novel xenograft model of tumor stage CTCL, where malignant T cells (MyLa2059) are transplanted to NOD/SCID-B2m(-/-) (NOD.Cg-Prkdc(scid) B2m(tm1Unc) /J) mice. Subcutaneous transplantation of the malignant T cells led to rapid tumor formation in 43 of 48 transplantations, whereas transplantation of non-malignant T cells isolated from the same donor did not result in tumor development. Importantly, the tumor growth was significantly suppressed in mice treated with vorinostat when compared to mice treated with vehicle. Furthermore, in most mice the tumors displayed subcutaneous and/or lymphatic dissemination. Histological, immunohistochemical and flow cytometric analyses confirmed that both tumors at the inoculation site, as well as distant subcutaneous and lymphatic tumors, originated from the transplanted malignant T cells. In conclusion, we describe a novel mouse model of tumor stage CTCL for future studies of disease dissemination and preclinical evaluations of new therapeutic strategies.