KLF4 gene silencing in T‐ALL will lead to aberrant activation of the mitogen‐activated protein kinase MAP2K7 and the downstream effectors c‐Jun NH(2)‐terminal kinase (JNK) and activating transcription factor 2 (ATF2) pathway, thus promoting the expansion of leukemia cells. The gene discussed is KLF4; the disease is acute lymphoblastic leukemia.