Cytogenetics adds independent prognostic information in adults with acute lymphoblastic leukaemia on MRC trial UKALL XA. MRC Adult Leukaemia Working Party.

Cytogenetic classification of 350 adults with acute lymphoblastic leukaemia on MRC UKALL XA trial showed the following statistically significant associations: t(9;22) (11%) increased with increasing age and leucocyte counts (WBC) and most had a C/pre-B immunophenotype. t(4;11) (3%) was associated with higher WBCs, increasing age and null immunophenotype. Other abnormalities of 11q (abn11q) (4%) were associated with male sex and T-cell ALL. High hyperdiploidy (7%) and abn9p (5%) decreased with increasing WBC. High hyperdiploid patients were younger and tended to have C/pre-B ALL. Triploidy/tetraploidy (3%) decreased and pseudodiploidy (11%) increased with increasing WBC. Cytogenetic classification was prognostically important (chi-square for heterogeneity of classification = 53.56; P < 0.0001) and added significance to age, sex and WBC. A poor prognosis for patients classed as t(9;22) (13% disease-free survival at 3 years), as t(4;11) 24% at 3 years) and hypodiploid (11% at 3 years), and good prognosis for abn12p (4% of subjects) and high hyperdiploidy (74% and 59% at 3 years respectively) were statistically significant, but the 54% 3-year disease-free survival for patients with t(1;19) was not. The prognosis of patients classed as t(9;22) was independent of other single variables. Abn12p, abnormalities of 11q (including t(4;11) cases) and hypodiploidy added prognostic significance to all other variables combined.