t(8;21) myelodysplasia: a further six cases

Philadelphia chromosome positive myelodysplastic syndrome and acute myeloid leukemia—retrospective study and review of literature

We conducted a retrospective study to define the significance of Philadelphia chromosome (Ph) in myelodysplastic syndrome and acute leukemia in the adults at this institution and the literature was reviewed. One hundred forty-eight cases of t(9;22)(q34;q11) were identified for the period September 1993 through August 2001. The presentation of 124 cases (84%) was that of typical CML in chronic phase. Nineteen cases (13%) presented as de novo ALL, two cases (1%) presented as de novo AML and three cases (2%) presented as myelodysplastic syndrome (MDS). The estimated incidences of t(9;22)(q34;q11) in ALL and AML are 21 and 0.6%, respectively. Ph+ AMLs are increasingly being reported with either M-BCR or m-BCR gene rearrangements, similar to those found with Ph+ ALL lending support to the notion that Ph+ AMLs are distinct entities and not merely blastic phases of undiagnosed CML. This is further supported by the existence of Ph+ MDS cases.

A rare variant translocation t(3;8)(q29;q22) without AML1/ETO fusion transcript in a case of oligoblastic leukemia

A 43-year-old man with oligoblastic leukemia and t(3;8) variant translocation is reported. At first he was classified as refractory anemia with excess of blasts in transformation according to the FAB criteria for myelodysplastic syndrome. Remission was obtained after intensive chemotherapy. After 8 months, a relapse occurred as overt M2 AML. At presentation chromosome study of bone marrow cells using R- and G-bandings revealed 45,X, -Y,t(3;8)(q29;q22) in 35 of the 42 metaphases analyzed and 46,XY,t(3;8) in one metaphase in addition to normal karyotype in the other six metaphases. However, RT-PCR assay showed no AML1/ETO fusion transcript. At relapse, a karyotype of 46, XY,t(3;8), deletion(4)(p14), add(7)(q32) was observed in all abnormal cells indicating a clonal karyotypic evolution. We believed that this case should be diagnosed as an early form of M2 AML initially. It may be the first case of oligoblastic leukemia with t(3;8) variant translocation. Further study is needed to elucidate its molecular entity.

Poor survival in t(8;21) (q22;q22)-associated acute myeloid leukaemia with leukocytosis

Twenty-nine consecutive cases with a t(8;21)(q22;q22) in the bone marrow (BM) karyotype were retrospectively studied concerning clinical, morphological and cytogenetic data. All had been diagnosed as acute myeloid leukaemia (AML), 27 FAB subtype M2 and two M1, comprising 5% of all cytogenetically analysed AML during 18 yr. Auer rods were the most consistent t(8;21)-associated morphological finding and were demonstrated in 92% of the reviewed BM specimens, whereas BM eosinophilia was seen in only 24%. The median age was 53 yr, and 30% of the patients were > 60 yr old. Twenty-four patients had received induction chemotherapy; 22 of these (91%) entered a complete remission (CR). The median survival time in treated patients was 18 months. Leukocytosis at diagnosis (> or = 20 x 10(9)/1) was significantly (p = 0.01) associated with shorter survival time. All four children are still in first CR after 9-80 months. Seven cases (25%) developed granulocytic sarcomas, discovered either at diagnosis (n = 4) or at first relapse (n = 3). Secondary chromosome abnormalities were found in 62% of the cases, most often loss of a sex chromosome. The presence of such secondary aberrations did not correlate with any morphological or clinical characteristics, including survival. This first Scandinavian study of AML with t(8;21) corroborates the previous findings that these AMLs are characterized by distinct morphological features, a high frequency of CR and a striking tendency to develop extramedullary leukaemic manifestations. Leukocytosis at diagnosis indicates a less favourable prognosis.

Diagnostic and prognostic significance of cytogenetics in adult primary myelodysplastic syndromes

Cytogenetic analysis has proven to be a mandatory part of the diagnosis of myelodysplastic syndromes (MDS) as well as a major indicator for predicting clinical course and outcome. This review concentrates on the cytogenetic classifications, the incidence and types of chromosome defects and the prognostic significance of the karyotype in adult primary MDS. Two cytogenetic classifications are currently used: one is based on the karyotype complexity (normal, single, double or complex defects), the other on clonal status (all metaphases normal, abnormal or admixture of normal and abnormal clones). Chromosome abnormalities are of both numerical and structural types. Aside from the 5q-syndrome, no specific clinico-cytogenetic entity has been reported. However, several distinct clinical and cellular features have been identified that correlate with the presence of specific chromosome defects such as inv(3)/t(3;3), +6, t(5;12), del(17p) and del(20q). The presence of complex defects is associated with reduced survival and a high risk of leukemic transformation. Among single defects, specific abnormalities may define distinct prognostic groups. Patients with del(5q) as a sole chromosome defect and a refractory anemia without excess of blasts have a favourable prognosis. For patients with trisomy 8 or monosomy 7 there may be distinct types of clinical evolution. Most patients with the 3q21q26 syndrome have a short survival. The presence of two chromosome defects may constitute an independent cytogenetic entity probably associated with relative poor prognosis. Karyotypic evolution generally represents a poor risk factor. The combination of cytogenetics with clinical and hematological features has proven to provide for a better prediction of patients' survival, leukemic transformation and response to treatment. Several scoring systems have been developed. They have to be improved by the study of new patients according to strict clinical and cytogenetic criteria and by the addition of newly recognized prognostic indicators such as histopathological features and molecular genetic mutations.