CYTOGENETIC STUDIES, RAS MUTATION, AND CLINICAL CHARACTERISTICS IN PRIMARY MYELODYSPLASTIC SYNDROME - A STUDY ON 68 CHINESE PATIENTS IN TAIWAN

Cytogenetics and clinical features were studied for as Chinese patient s with primary myelodysplastic syndrome (MDS). Pas mutation was analyz ed in 25 of them. Thirty-four patients (50%) had clonal chromosomal ab normalities at initial analysis. The most common cytogenetic aberratio ns were -7, +8, 5q-, and 20q-, which occurred in 11 (16.2%), seven (10 .3%), five (7.4%) and three patients, respectively. The incidence of - 7 was higher and that of 5q- lower in our patients than in patients fr om most other geographic areas. The 17 patients with multiple chromoso mal abnormalities had a significantly shorter median survival (9 month s) than the 34 patients with normal karyotype (33 months) and the 17 p atients with patients with single anomalies (26 months). Evolution to acute leukemia occurred in 20 patients (29%) after a median interval o f 8 months following the diagnosis. Patients with multiple cytogenetic changes at initial analysis or in subsequent studies had a significan tly higher frequency of acute transformation than others (55% vs. 18.6 %, p = 0.007); the same was not true if only the data of initial study were considered. Serial cytogenetic studies are important in patient follow-up. N-ras mutation was detected in 5 (20%) of 25 patients withi n the study. There was no correlation between the gene mutation and ac ute transformation. But combing the data of N-ras mutation and cytogen etics, patients with either the N-ras mutation or clonal chromosomal a bnormalities were at significantly higher risk for developing acute le ukemia than those with neither of the changes (77% vs. 25%).