Other frequent genetic lesions include mutations that activate the NOTCH pathway, which are present in approximately 40% of SMZL and NZML cases but in less than 5% of MALT lymphomas, and mutations that inactivate the transcription factor KLF2, which are detected in 20–40% of SMZL and 20% of NZML cases (reviewed in Reference [136]). The gene discussed is KLF2; the disease is MALT lymphoma.