Conventional and molecular cytogenetic features of myelodysplastic syndrome in China

Myelodysplastic syndrome (MDS) constitutes a heterogeneous group of hematopoietic stem cell disorder characterized by peripheral blood cytopenia(s), in the presence of hypercellular bone marrow with features of ineffective hematopoiesis, and susceptibility to acute leukemia (AL). Although the precise pathogenesis of MDS remains to be clarified, cytogenetic abnormalities seem to be involved in its pathogenesis and are considered as an important factor in diagnosis and predicting clinical outcome.

To explore the cytogenetic features of Chinese patients with myelodysplastic syndrome (MDS).

Conventional cytogenetic analysis was performed in 88 MDS patients and among them, 34 cases were studied by interphase fluorescence in situ hybridization (I-FISH) with precisely chromosome 8 centromere specific DNA probe and DNA specific probes for 7q32 , 5q31.

Of the 88 patients, 45 (51.1%) showed clonal karyotypic abnormalities by CC at diagnosis, including numerical changes (18 cases, 20.5%), structural changes (12 cases, 13.6%), and numerical and structural changes simultaneously(15 cases, 17.0%). Trisomy 8, -5/5q-, and -7/ 7q- account for 20.5%, 15.9%, and 5.7% respectively. Complex karyotypes were observed in 17 patients, the incidence being 19.3% in the whole series of cases. Among 34 MDS patients studied by I-FISH, -5/5q-, -7/7q- and trisomy 8 occurring in 4, 2 and 10 cases respectively for CC were confirmed by I-FISH. 5 cases in 30 cases who did not show -5/5q- by CC displayed this abnormality by I-FISH. 3 cases without -7/7q- by CC presented this aberration by I-FISH. 5 cases with trisomy 8 for I-FISH was not identified this change by CC.

The frequent abnormalities are trisomy 8, -5/5q- and -7/ 7q-. FISH is very useful in detecting these alterations in MDS and it is an important complement to CC.