Cytogenetic aberrations in adult acute lymphocytic leukemia: optimal technique may influence the results.

The aim of the present study was to analyse the distribution of cytogenetic aberrations in adult ALL in a population based material and compare the results with literature data. Forty-one patients were diagnosed during a 12-year period. The age varied between 14 and 82 (mean 37, median 32). Thirty-two patients were cytogenetically investigated and in all cases analysable metaphases were obtained (range 10-29, mean 24, median 25, success rate: 100%). Nine (28%) patients had a T-phenotype and 23 (72%) had a pre-B phenotype. High hyperdiploidy was found in four patients (13%). Hypodiploidy was found in 5 patients (16%), 10 (31%) had a pseudodiploid chromosome mode and four (13%) showed low hyperdiploidy (chromosome mode 47-51). Chromosomes 10 and 18 were most frequently involved in numerical aberrations. Structural aberrations most frequently involved chromosomes 6, 9 and 22. t(9;22) was seen in six cases (19%), del(6q) in five cases (16%) and der(9p) in five cases (16%). High hyperdiploid clones, which are associated with a favorable prognosis, were found with the same frequency as in other studies. The frequency of t(9;22) was 19% in our study, others have found frequencies between 11% and 30%. Compared to previously published studies our patients with t(9;22) were younger. Furthermore, those with del(6q) were older, showing a median age equivalent to the patient group as a whole. The differences between our data and previously published studies may be explained by population-based derived data and especially by an optimal technique in obtaining metaphases.