OBJECTIVE: To investigate the value of interphase fluorescence in situ 
hybridization(FISH) in the detection of monosomy 7 (-7)or deletion of long arm 
of chromosome 7(7q-) in the cases of myelodysplastic syndrome (MDS).
METHODS: Forty-six cases of MDS and 10 normal controls were studied 
simultaneously by conventional karyotype analysis and interphase FISH technique 
using SpectrumRed directly labeled DNA specific probe for 7q32. Two hundred 
interphase cells were analyzed for each case and the cells with one red 
hybridization spot<7% were regarded as positive.
RESULTS: Three cases displayed -7/7q- by conventional cytogenetics(CC) and were 
confirmed by interphase FISH. Six cases in 43 cases who did not show -7/7q- by 
CC displayed -7/7q- by interphase FISH.
CONCLUSION: Interphase FISH is very useful for the detection of -7 or 7q- in MDS 
and it is more sensitive than CC.