OBJECTIVE: To explore the value of interphase fluorescence in situ hybridization 
(FISH) in the detection of trisomy 8 in myelodysplastic syndromes (MDS).
METHODS: Conventional cytogenetics (CC) and interphase FISH using SpectrumGreen 
labelled chromosome 8 centromere specific probe were simultaneously carried out 
to detect trisomy 8 in 69 MDS and 6 normal individuals.
RESULTS: Two hundred interphase cells were counted and cells with three green 
hybridization spots > 3% was assigned. Eleven cases displayed trisomy 8 by CC 
and were confirmed in 10 by FISH. In 7 cases, the percentage of trisomy 8 cells 
was significantly lower by FISH than by CC. Seven cases displayed trisomy 8 by 
FISH in 58 cases who did not show trisomy 8 by CC. Of the 7 cases, two had 2 and 
3 marker chromosomes respectively, 4 had normal karyotypes.
CONCLUSIONS: Interphase FISH was a useful method for the detection of trisomy 8 
in MDS, especially in patients with normal karyotype or marker chromosome. It 
was a important complement to CC.