Targeted deletion of miR-15 and miR-16 in mice at the age of 18 months recapitulates the spectrum of CLL-associated lymphoproliferations in humans, including CLL, CD5(+) monoclonal B-cell lymphocytosis, and CD5- non-Hodgkin lymphomas (17). This evidence concerns the gene CD5 and B-cell chronic lymphocytic leukemia.