In 13q14 deleted patients, exclusive RNA polymerase III-driven transcription was observed and found to associate with high expression of ZAP70. Indeed, in a CLL case of monozygotic twins that differed in ZAP70 status and clinical features, transcription of primiR-15a/16-1 was driven by RPIII in the aggressive ZAP70-positive patient and by RPII in the indolent ZAP70-negative case [27]. The gene discussed is ZAP70; the disease is B-cell chronic lymphocytic leukemia.