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). This evidence concerns the gene CD4 and synovial sarcoma.