Tumor Clone Frequency Calculation Using High-Throughput Sequencing of the TCRβ Gene in Patients with Folliculotropic Mycosis Fungoides.

Cutaneous T-cell lymphomas are a heterogeneous group of lymphoproliferative disorders defined by the clonal expansion of malignant T lymphocytes in the skin. Classic mycosis fungoides (MF) is the most common type, accounting for 60% of cutaneous T-cell lymphomas, and >70% of these patients present with early-stage disease (≤IIA), corresponding with an indolent disease course (Agar et al., 2010; Willemze et al., 2019). These patients are characterized by infiltration of malignant T lymphocytes in the epidermal epithelium (epidermotropism) and clinically by flat erythematous, scaly patches, or more elevated plaques typically localized on sun shielded areas (Willemze et al., 2005).