Interphase fluorescence in situ hybridization overcomes pitfalls of G-banding analysis with special reference to underestimation of chromosomal aberration rates

Fluorescence in situ hybridization (FISH) is suitable for detecting differe nt types of chromosome aberrations on interphase nuclei even in specimens w ith no or few chromosome metaphases. However, it is not known why FISH is s uperior to conventional G-banding analysis. The sensitivity of interphase F ISH was compared to that of G-handing analysis in 288 leukemia/lymphoma pat ients for 10 different types of chromosome aberrations: t(9;22) (M- and m-B CR), t(8;21), 11q23 abnormalities, t(15;17), del(5)/-5, del(13)/-13, +8, -7 , and +12. The results revealed that t(15;17) positive cells could not prol iferate well in culture, leading to underestimation of abnormality by G-ban ding, Monosomy 7 in acute myelocytic leukemia (AML) and myelodysplastic syn drome (MDS) as well as trisomy 12 and deletion chromosome 13 in chronic lym phocytic leukemias (CLL) were also severely underestimated by G-banding. On the other hand, no discrepancies were observed in t(8;21), t(9;22), transl ations involving 11q23, or in trisomy 8. These findings indicate the superi ority of interphase FISH over conventional cytogenetics for detecting chrom osome abnormalities in small clones, especially for monosomy 7 or (15;17) t ranslocations. (C) Elsevier Science Inc., 1999. All rights reserved.