INTERPHASE CYTOGENETIC STUDY OF CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA

We used the fluorescence in situ hybridization (FISH) technique and ce ntromere-specific probes for chromosomes 1, 6, 8, 10, 12, 17, 18, X, a nd Y to investigate the presence and number of the respective chromoso mes in interphase nuclei of 14 cases of childhood acute lymphoblastic leukemia (ALL) which were shown to be hyperdiploid by DNA flow cytomet ry irrespective of their cytogenetic pattern. Numerical anomalies for one or more chromosomes were detected in all 14 cases. The FISH result s were compared with those obtained by conventional cytogenetic analys is. A hyperdiploid karyotype was evident in 5 cases, the others were e ither normal or lacking cytogenetic results because of technical failu re. In the 5 cytogenetically hyperdiploid cases, 14 numerical abnormal ities were observed with both techniques, whereas 4 numerical deviatio ns were found only with FISH. In 9 other cases which had a DNA content indicating hyperdiploidy, 34 trisomies and 2 tetrasomies were detecte d by FISH analysis. Furthermore, in 1 case duplication of the Y chromo some and in 3 male cases duplication of the X chromosome were evident. Double-target FISH experiments in 2 patients allowed the correlation of numerical aberrations of 2 chromosomes in one and the same cell. By such analyses, detection of subpopulations of tumor cells was found t o be relatively easy. Our results indicate that the FISH technique wit h chromosome-specific repetitive centromeric probes is a rapid, simple to use, and easy to interpret technique for the evaluation of numeric al chromosomal aberrations in interphase nuclei of leukemias. (C) 1994 Wiley-Liss, Inc.