OBJECTIVETo exploit the role of bone marrow (BM) and peripheral blood (PB) fluorescence in situ hybridization (FISH) in cytogenetic evaluation of myelodysplastic syndrome (MDS).

METHODSThe metaphase cytogenetics and BM interphase FISH were prospectively compared in 112 cases of de novo MDS. At the same time, comparison of BM and PB FISH was conducted in 56 cases.

RESULTSThe differences between metaphase cytogenetics and BM FISH were observed in 22 (54%) of 41 cases with clonal karyotypic abnormalities, most of differences were caused by the limitation of FISH probe panel which could not target all of the regions with aberrations. Only 6 (27%) of 22 differences were involved in our probe regions, the FISH results did not change their cytogenetic risk categories. BM FISH testing was abnormal in 15 (21%) of 71 cases with normal karyotypes, FISH testing was abnormal in 14/51 (27%) and 1/20 (5%) cases with fewer than 20 normal metaphases or more than 20 normal metaphases. Comparison of FISH results of PB and BM samples showed abnormal PB FISH results in 21 (72%) of 29 cases with abnormal BM FISH results, and in 1 (4%) of 27 cases with normal BM FISH results.

CONCLUSIONBM FISH should be used to MDS cases with fewer than 20 normal metaphases. Although PB FISH testing is limited by a relatively high false negative rate, it is a reasonable choice to cases with failure of BM aspiration.