RCC1 and B-cell chronic lymphocytic leukemia: Here, we have characterized 10 further cases of CLL with t(1;6)(p35.3;p25.2) and show that this translocation involves directly and recurrently the gene‐encoding interferon regulatory factor 4 (IRF4) on chromosome 6p25.2 with the regulator of chromosome condensation 1 (RCC1) gene on chromosome 1p35.3.