IKZF1 and lymphoma: Likewise, constitutive expression of ZBTB7B during thymopoiesis propagates a preleukemic and self-renewing DN4 lymphoma progenitor population with mutations leading to enhanced NOTCH1 signaling and/or repressed tumor suppressors IKZF1 (Ikaros) & PTEN, which gives rise to T-cell lymphomas in the periphery (189).