[WHO classification and cytogenetic analysis of 435 cases with myelodysplastic syndrome].

OBJECTIVE

To investigate the WHO classification and cytogenetic characteristics of primary myelodysplastic syndrome (MDS) in adults of Shanghai area and then compare them with those of western countries.

METHODS

The consecutive samples of 435 patients with MDS in Sino-US Shanghai Leukemia Cooperative Group were collected prospectively and diagnosed with WHO classification. Cytogenetic analysis was performed using chromosome G-banding and fluorescence in situ hybridization (FISH) techniques.

RESULTS

The median onset age in the patients was 58 (18-90) years. The proportion of cases with refractory cytopenia with multilineage dysplasia (RCMD) was highest ,accounting for 69.6% (303/435). Other subtypes were refractory anemia with excess blasts (RAEB) 24.1% (105/435), refractory anemia (RA) 2.3% (10/435), myelodysplastic syndrome, unclassifiable (MDS-U) 2.3% (10/435), refractory anemia with ringed sideroblasts (RAS) 1.2% (5/435) and 5q-syndrome 0.5% (2/435) in turn. The proportions of RA, RAS and 5q-syndrome were higher in western countries and RCMD subtype was lower. Eleven cases had failure of chromosome analysis. In the remaining 424 cases with success the frequency of chromosome abnormality was 38.7%, with the highest in RAEB- I (62.5%), and then RAEB-II (48.4%) and RCMD (34.5%) in turn. The sequence of common chromosome abnormalities was + 8 (12.7% ), complex karyotype (9.0%), chromosome translocation (7.8%), - 20q (6.6%), -7/-7q (5.2%), -5/-5q (4.2%) and- Y(2.4%), while the sequential order in western countries -5/-5q, -7/-7q, +8, 11q and 12p/12q. Chromosome prognosis was grouped according to International Prognosis Scoring System (IPSS), 289 cases were in the group with good chromosome prognosis (68.2%), 81 cases in group with medium prognosis (19.1%) and 54 cases in group with poor prognosis (12.7%). Seventeen patients had normal chromosome examination because of lower percentage of abnormal cells. However, the detection sensitivity of abnormality with FISH may sometimes be high.

CONCLUSIONS

The WHO subtype and chromosome abnormality distributions of MDS in Shanghai were different from those in western countries. The combination of FISH and conventional chromosome examination could improve the detection sensitivity.