Chromosome aberrations in B-cell chronic lymphocytic leukemia. Pathogenetic and clinical implications.

Chromosome analyses were performed on leukemic cells from 102 patients with B-CLL, of whom 84 were untreated. B-cell mitogen-induced CLL cells yielded suitable metaphases in 85 patients, and 55 showed clonal chromosomal aberrations. Trisomy 12 was found in 26 patients. In nine patients the + 12 was a single aberration. A 14q + chromosome or deletions of the long arm of chromosomes 6, 11, or 13 were other recurrent aberrations. Patients with Rai stage I or more had more frequently clonal aberrations than patients with stage 0 disease (p less than .02). Patients with clonal aberrations had poorer 5-year survival than those with a normal karyotype (p less than .05). Patients with a high percentage of abnormal metaphases in the sample had poorer prognosis than patients with high admixture of normal metaphases (p less than .01). Of the specific clonal aberrations those with 14q + or trisomy 12 tended to have slightly poorer and those with 6q- or structural aberrations involving the long arm of chromosome 13 tended to have better prognosis than patients with other chromosomal aberrations. A complex karyotype tended to be an adverse prognostic sign. Clonal evolution is rare: complex karyotypes are found at diagnosis and clones with single aberrations did not acquire additional chromosome aberrations despite progressive disease and treatment. Nine hundred and seventy-nine published cases are reviewed, and pathogenetic mechanisms, such as oncogenes and gene dosage, are discussed.