To determine the expression of endogenous XPO1 protein in CTCL, we first performed a western blot analysis in CD4+ T cells from two healthy donors and five well-characterized CTCL cell lines (MyLa, MJ, H9, Hut78, and HH), originally obtained from patients with mycosis fungoides (MF) and Sézary syndrome (SS). The gene discussed is XPO1; the disease is primary cutaneous T-cell non-Hodgkin lymphoma.