OBJECTIVE: To identify the abnormal karyotypes by fluorescence in situ 
hybridization (FISH) and explore prognostic implications in patients with 
myelodysplastic syndromes (MDS).
METHODS: FISH was used to detect the frequently occurring chromosome 
abnormalities (-5/5q, +8, -7/7q-) in 37 MDS cases. SPSS 11.5 software and 
correlation analysis were used to analyze the relativity among the abnormal 
chromosomes, the prognosis and the disease conversion in 37 MDS patients.
RESULTS: Karyotype abnormalities were found in 21 (56.8%) of 37 cases, among 
which 6 (16.2%) were complex karyotypes, 9 (24.3%) +8, 2(5.4%) -5/5q-, 2(5.4%) 
-7/7q-. In the median time of follow-up of 12 months, 12 cases transformed into 
acute leukemia. Complex karyotypes were significantly associated with the poor 
prognosis and leukemia transformation. + 8 and -7/7q- abnormalities were 
correlated with the death.
CONCLUSIONS: FISH was more sensitive than conventional cytogenetics for 
detecting mini-clonal abnormality. There are some differences in abnormal 
karyotypes between patients in China and the western countries. Multi-probes 
used in cytogenetic detections may predict the patient' s prognosis more 
accurately. The higher proportion of abnormal karyotypes the poorer prognosis.