Leukemic transformation in patients with the 5q- alteration: analysis of the behavior of the 5q- clones in preleukemic to leukemic phases

Cytogenetic evolution correlates with poor prognosis in myelodysplastic syndrome

Clonal chromosomal abnormalities are observed in 30-50% of primary myelodysplastic syndrome (MDS) patients. Although the prognostic relevance of cytogenetics is generally appreciated, the prognostic value of cytogenetic evolution has rarely been evaluated. In this study, we retrospectively analyzed cytogenetic features at diagnosis and during follow-up in 85 patients with primary MDS. Cytogenetic evolution occurred in 18 of the 85 patients (21%), with chromosomes 8, 5, and 1 most often involved. Patients with higher levels of marrow blasts (P = 0.034), more advanced stages of World Health Organization (WHO) subtypes (44% vs. 16%, P = 0.035), and higher risk International Prognostic Scoring System (IPSS) subgroups (47% vs. 16%, P = 0.021) had higher incidences of developing cytogenetic evolution. Furthermore, the median survival of patients in the group with cytogenetic evolution was 25.8 months, compared with 45.4 months for patients in the group without cytogenetic evolution (P = 0.01). The same result was also found for time to progression: patients with cytogenetic evolution progressed more rapidly than those without cytogenetic evolution (P = 0.007). Knowledge of cytogenetic evolution offers useful information for clinicians to make more accurate prognostic assessments for patients with MDS.

Adequate cytogenetic examination in myelodysplastic syndromes: analysis of 529 patients

In myelodysplastic syndromes (MDS), the karyotype is one of the most significant prognostic markers with profound impact on differential diagnosis and therapeutic decisions. In a retrospective study, we examined karyotypes of bone marrow specimens of an oligocentric cohort comprising 529 patients with MDS to address the question how many metaphases need to be analyzed to detect even small cell clones with an appropriate expenditure. We found a statistically significant difference of the frequency of normal karyotypes in the patient group with 19 or less analyzed metaphases compared to the group with 20 or more metaphases analyzed (56% versus 47%, p=0.041). Furthermore, we demonstrate that the analysis of 25 or more metaphases can further improve the sensitivity of karyotype analysis and leads to the identification of additional clinically relevant abnormal clones or subclones in a substantial proportion of patients. In summary, our data suggest the examination of at least 20 metaphases in MDS.

Cytogenetic findings in 179 patients with myelodysplastic syndromes

Cytogenetic analyses were performed on 266 bone marrow and peripheral blood samples from 179 patients with myelodysplastic syndromes (MDS). According to the FAB classification, 42 patients presented with RA, 18 with RARS, 37 with RAEB, 22 with CMML, and 29 with RAEB-T. Nine patients showed a secondary MDS (S MDS). FAB classification was not available for 22 patients. Clonal karyotype anomalies were found in 92 patients (51.4%). Complex chromosome abnormalities occurred in 17 (18.5%) of them. An evolution of the karyotype was detected in 16 cases (17.4%). Cytogenetically independent cells or cell clones were found in eight patients. Nonclonal chromosome abnormalities were uncovered in 29 (16.2%) of the 179 MDS patients. Consecutive studies were performed in 48 patients and revealed a good correlation of initial karyotype and clinical course. The most frequent single anomalies were 5q- in 29 (31.5%), -7 in 22 (23.9%), trisomy 1q in 14 (15.2%), and +8 in 13 (14.1%) of 92 patients respectively. Our cytogenetic findings are presented in detail and discussed in relation to patients' age, morphological classification, clinical course, and prognostic impact. The contribution of cytogenetic findings to the delineation of multistep pathogenesis of MDS with special emphasis to karyotype instability is demonstrated.

5q- anomaly preceding acute myeloblastic leukemia with 53 chromosomes without chromosome 5 abnormality

Partial deletion of the long arm of chromosome 5 (5q-) was found in a patient with a myeloid disorder. After treatment, hematologic parameters became normal, but acute myeloblastic leukemia occurred after 58 months. At that time, cytogenetic studies showed the presence of an abnormal clone with 53 chromosomes and without 5q-. This exceptional case suggests that the 5q- abnormality may precede the occurrence of an acute leukemia in favoring the appearance of unrelated malignant clones.

Cytogenetic biclonality in malignant hematologic disorders

Generally, malignant hematologic disorders have been believed to be of monoclonal origin. However, cytogenetically unrelated clones have been reported in some disorders including one case of acute leukemia (AL), one of acute lymphoblastic leukemia (ALL), one of acute myeloblastic leukemia (AMMoL), and five of myelodysplastic syndromes (MDS). The most frequent chromosome abnormality was trisomy 8 (75%), followed by trisomy 21 (37.5%, including tetrasomy 21) and trisomy 11 (25%). Two patients showed both trisomy 8 and 11, one also had trisomy 21 (triclonal). One patient showed two cytogenetically distinctive clones in which one was 47,XY,+8, related to myeloid cells, and the other had a del(6q) and del(9p), suggesting lymphoid cells. One patient we report and 5 from the literature had two unrelated clones with trisomy 8 and deletion of the long arm of chromosome 5 (5q-); all had MDS. Review of our records showed that 11 patients with both trisomy 8 and 5q- in the same abnormal karyotype (not biclonal) had AL, i.e., 10 of acute nonlymphocytic leukemia (ANNL) and one of chronic myelogenous leukemia (CML) in blastic crisis. These findings suggest that cytogenetically unrelated clones may indicate hematopoietic biclonality.

Clonal evolution in primary 5q-syndrome

Primary 5q-syndrome is a type of myelodysplastic syndrome characterized by refractory anemia, thrombocytosis, and hypolobulated megakaryocytes. The risk of leukemic transformation is low. A case of 5q- syndrome that occurred in a 42-year-old woman and was complicated by leukemic transformation 7 years after the initial diagnosis is reported. An additional clonal karyotypic anomaly, del(7q), was seen in the leukemic cells. The literature on leukemic and karyotypic evolution of primary 5q- syndrome is reviewed and the implication of karyotypic evolution is discussed.

Cytogenetic peculiarities in chronic myelogenous leukemia

Cytogenetic investigations were performed in 185 patients with chronic myelogenous leukemia (CML) at all stages of the disease; 166 patients were Ph positive-159 (95.8%) of these showing the standard Ph translocation, and 7 (4.2%) variant translocations-17 patients were Ph negative. In 2 patients the cytogenetic analysis was unsuccessful. Additional aberrations were found in 40 (24.1%) of the Ph-positive patients. Nine (52.9%) of the Ph-negative patients showed chromosome anomalies. Besides the well known nonrandom abnormalities (-7, +8, i(17q), +19, +Ph) we found a high frequency of clones with rare or not yet described structural rearrangements--in 14 cases (34.2%) of the Ph-positive patients and in 2 cases (20%) of the Ph-negative patients with other chromosome abnormalities. The clinical significance of these findings is discussed.

5q- syndrome terminating in acute myeloid leukemia. Karyotype evolution and immunologic characterization of blast cells

We report a case of 5q- syndrome that progressed to acute nonlymphocytic leukemia after 9 years of clinically and morphologically stable disease. The transition from the chronic to the leukemic phase was characterized by the appearance of an additional cytogenetic anomaly [inv(2)] in the cell carrying the 5q-, together with the expansion of a clone showing an apparently normal karyotype.