Chromosome analysis on CLL-cells from 649 patients revealed clonal changes in 311 cases (48%). The most common abnormalities were trisomy 12 (n = 112), and structural changes on the long arm of chromosome 13 (n = 62), most of them interstitial deletions or translocations involving 13q14, the site of the retinoblastoma gene. Complex karyotypes were associated with poor prognosis, although karyotypic changes rarely develop during the course of the disease. Among patients with single chromosomal abnormalities those with trisomy 12 had a poor survival, whereas those with structural changes on chromosome 13 had as good a prognosis as patients with a normal karyotype.
Keywords: CLL; Cytogenetic findings; survival.