Prognostic significance of chromosome abnormalities in chronic lymphocytic leukaemia.

Lymphocytes from 33 out of 63 patients with B-cell chronic lymphocytic leukaemia (B-CLL) were successfully stimulated for cytogenetic analysis by means of two B-cell mitogens: pokeweed mitogen and lipopolysaccharide-B, used after pretreatment of the cells with neuraminidase and galactose oxidase. All patients had abnormal clones in 30-100% of the cells analysed. Chromosomes more frequently involved were Nos. 1, 3, 6, 11, 12, 13 and 14. The most common abnormality was a marker 14q+ (breakpoint 14q32) seen in 17 cases; trisomy 12 was observed in seven cases. A clinical scoring system was used to investigate the correlation of chromosome abnormalities with prognosis. The group with 14q+ was often associated with features of progressive disease, namely; prolymphocytoid or Richter transformation, refractoriness to therapy, high WBC and advanced staging. A significant difference in survival was observed between patients with 14q+ and the rest: median survival from diagnosis being 45 months and over 64 months, respectively (P less than 0.05); when survival was calculated from the time of chromosome analysis the values were 8 months and more than 41 months, respectively (P less than 0.01). It is suggested that 14q+ is acquired during the evolution of CLL and that this development may be a key event in the clinical progression of B-CLL. Other abnormalities, including trisomy 12, were not found to be associated with a worse prognosis.