High IKZF2 Expression in Malignant T cells Promotes Disease Progression in Cutaneous T cell Lymphoma

Cutaneous T cell lymphoma is a generally indolent disease derived from skin-homing mature T cells. However, in advanced stages, CTCL may manifest as aggressive clinical behavior and lead to a poor prognosis. The mechanism of disease progression in CTCL remains unknown. Here, with a large clinical cohort, we identified that IKZF2, an essential transcription factor during T cell development and differentiation, showed stage-dependent overexpression in the malignant T cells in MF lesions. IKZF2 is specifically over-expressed in advanced-stage MF lesions, correlates with poor patient prognosis. Mechanistically, IKZF2 overexpression promotes CTCL progression via inhibiting malignant cell apoptosis and may contribute to tumor immune escape by downregulating MHC-II molecules and up-regulating the production of anti-inflammatory cytokine IL-10 by malignant T cells. These results demonstrate the important role of IKZF2 in high-risk CTCL and pave the way for future targeted therapy.