The study is based on a consecutive series of 176 newly diagnosed and phenotypically typical CLL (median Matutes score: 5; range 4-5) [7, 8] , representative of all disease stages. The biological and clinical characteristics of the CLL series are reported in Table I . By FISH, gain of REL was observed in 6/176 (3.4%) cases, gain of BCL11A in 5/176 (2.8%), and gain of MYCN in 4/176 (2.3%). The median percentage of nuclei harboring gains was 46.8% (range: 18.0-85.0%) for REL, 66% (range: 14.0-77.4%) for BCL11A, and 78.2% (range: 45.0-90.0%) for MYCN. The number of additional copies was 1 for REL, 1 for BCL11A, and 1 for MYCN. REL, BCL11A, and MYCN were concomitantly gained in the same clone in 4/176 (2.3%) cases. REL and BCL11A, but not MYCN, were concomitantly gained in the same clone in 1/176 (0.5%) cases. In 1/176 (0.5%) cases, the sole REL gene was gained.