MEN1 and B-cell chronic lymphocytic leukemia: In addition, the positive correlation between miR-15a and miR-16-1 in the Men1+/− mouse pituitary tumours (Fig. 1) indicates that these miRNAs are likely transcribed as a polycistronic cluster, under the control of the same promoter elements, as reported for these miRNAs in patients with chronic lymphocytic leukaemia (CLL) (Calin et al. 2008).