Hematologic and clinical features of patients with chromosome 5 monosomy or deletion (5q)

Translocation (12;17)(q13;q23) in de novo acute myeloid leukemia with trilineage myelodysplasia

12q13 abnormalities have been reported to be associated with a variety of benign and malignant solid tumors. Recently, they have been shown to be a nonrandom karyotypic change in acute myeloid leukemia. We report a case of de novo acute myeloid leukemia with trilineage myelodysplasia showing t(12;17)(q13;q23) as the sole chromosomal abnormality. A review of the literature indicates that 12q13 translocation in acute myeloid leukemia is often associated with concomitant dysmyelopoietic changes. There is also evidence to suggest that 12q13 translocation occurs more frequently in acute myeloid leukemia with a prior history of mutagenic exposure or karyotypic indicators of secondary leukemia.

5q- syndrome in a child

A boy aged 8 years, 10 months presented with refractory anemia. Bone marrow investigation revealed monolobular megakaryocytes. Cytogenetic analysis showed a clonal abnormality: 46, XY, del(5)(q14q32). This is the youngest individual ever reported with this disorder. A year after diagnosis, while on treatment with human recombinant erythropoietin, the bone marrow showed an excess of blasts. No bone marrow donor could be found. Transformation to acute myelomonocytic leukemia occurred 3 months later. In spite of intensive chemotherapy, the child died of progressive disease with massive splenomegaly and jaundice. The case illustrates that the 5q- syndrome can occur de novo in children. The outcome in this child was poor, which may reflect a difference from the adult 5q- syndrome or may possibly be related to the erythropoietin the child received.

12q13, a new recurrent breakpoint in acute non-lymphoblastic leukemia

The karyotypes of 312 successfully analyzed samples of children with acute non-lymphoblastic leukemia (ANLL), which were sent to us by 72 German hospitals, were examined in order to find new recurrent chromosome abnormalities of possible clinical relevance. Whereas most of the patients had one of the specific aberrations of ANLL or a normal karyotype, random numerical or structural changes were found in 61 children (20%). Four of them showed an abnormality involving band 12q13: t(12;17)(q13;q21), t(12;21)(q13;q21), t(2;12)(p13;q13), and t(5;12)(p11;q13). Despite the fact that FAB subtypes were different (M0, M1 M6, AHL), the blasts of all patients were characterized by immaturity and were difficult to classify. The breakpoint 12q13 might be of clinical importance in ANLL, because the four patients in our study, as well as the 21 patients with this aberration found in the literature, had a very poor prognosis.

Karyotype in myelodysplastic syndromes: relations to morphology, clinical evolution, and survival

One hundred eighty-eight unselected consecutive patients with "de novo" myelodysplastic syndrome (MDS) were studied cytogenetically. They were subclassified as 4 refractory anemia with ringed sideroblasts (RARS), 67 refractory anemia (RA), 58 refractory anemia with excess of blasts (RAEB), 40 RAEB in transformation (RAEB-t), and 19 chronic myelomonocytic leukemia (CMML). The overall incidence of chromosome abnormalities was 69%. The RAEB and RAEB-t patients showed karyotypic changes, more often than RA and CMML (76% and 100% vs. 56% and 42%, respectively). The most frequent single anomaly was del(5)(q13-q22q33) (22 cases), followed by monosomy 7 or del 7q (11 cases), del(11) (q14q23) (8 cases), trisomy 8 (4 cases). Complex karyotypes (defined by the presence of three or more structural or numerical abnormalities) were detected in 33 patients. With regard to the FAB classification, del (5)(q13q33) was associated with RA, and complex rearrangements with RAEB and RAEB-t. Leukemic transformation occurred in 66 patients (46%), none with a normal karyotype or del(11)(q14q23) as single abnormality. In patients carrying 5q- alone, acute evolution correlated with proximal breakpoint localization, being found in no case with del(5)(q13q33) but in three out of four cases with del(5)(q22q33). Acute leukemia (AL) progression happened in all cases with complex rearrangements and monosomy 7 or del(7q). Two of the four trisomy eight patients evolved in AL. By using the Cox proportional hazard regression analysis it was demonstrated that the karyotype abnormality was a significant predictor of leukemic transformation (P < 0.001). Patients with abnormal karyotypes without complex abnormalities had a survival (median survival 12 months) shorter than that of cases with only normal metaphases (median 83 months) (P < 0.001); patients with a mixture of normal/abnormal metaphases had a median survival of 31 months. The median survival for complex karyotypes was 7 months. Among cases with single defects, del(5)(q13q33) showed the best survival (64 months), monosomy 7 and del(7q) the worst (7 months) (P < 0.001).

De novo acute leukemia with a sole 5q-: morphological, immunological, and clinical correlations

The 5 q deletion is frequently found in myelodysplastic syndromes and acute non lymphoid leukemia, but this anomaly is usually found in secondary diseases and associated with many other chromosomal aberrations. This report describes four cases of "de novo" acute leukemia with a sole 5q- anomaly. They had no cytological, genetic or clinical characteristics of secondary disorders. It is important to note that of the four patients studied, three had proliferation of immature blast cells. One case was classified as a MO AML and two as "undifferentiated" acute leukemia. Furthermore, these four cases of acute leukemia showed a deletion of the same portion of the long arm of chromosome 5: q22q33. On the same part of this chromosome many hematopoietic growth factor genes have been located, like IL3 and GM-CSF which have early undifferentiated hematopoietic stem cells as a their target.

del(5q) in acute lymphoblastic leukemia with biphenotypic and early progenitor phenotype

We report three patients with acute lymphoblastic leukemia with biphenotypic and early progenitor phenotype who had del(5q). In the first patient, the del(5q) was the sole abnormality; in the second patient, the del(5q) was interpreted as subclonal evolutionary event; while in the third patient, the rearrangement was transiently present 7 months following the diagnosis of Ph-positive ALL, while the patient was in clinical remission. Review of the literature indicates that del(5q) is rare in ALL. In contrast to its presence in AML, del(5q) in ALL is not an adverse prognostic indicator, and it appears to be more frequent in children.

Deletion of the long arm of chromosome 5 in essential thrombocythemia

A 51-year-old woman with no history of prior chemotherapy or radiation therapy was diagnosed with essential thrombocythemia (ET) according to the diagnostic criteria established by the Polycythemia Vera Study Group (PVSG). Cytogenetic analysis of bone marrow metaphases revealed both normal female karyotype and a single clonal abnormality, 46,XX,del(5)(q22q35). While chromosomal abnormalities have been reported in ET, their incidence is very low, and no specific abnormality has been found. Many of the reported cases of ET with chromosomal aberrations, including 5q-, do not meet the diagnostic criteria proposed by the PVSG, and may represent one of the other myeloproliferative disorders or a myelodysplastic syndrome. Furthermore, it is important to distinguish the 5q- syndrome, which may present with thrombocytosis and megakaryocytic hyperplasia, from ET. Our patient appears to be the first example of untreated ET clearly meeting the PVSG criteria in which 5q- was the only clonal abnormality seen at diagnosis.

Hybrid leukemia and the 5q-abnormality

Most cases of acute leukemia with deletions of chromosome 5q (5q-) are acute myelogenous leukemia. 5q- in acute lymphoid leukemia is rare. We studied a case of acute leukemia with 5q- using morphologic, cytochemical, immune and molecular techniques. Morphologic and cytochemical techniques were consistent with ALL (FAB L-2, PAS+, MPO-, ASD-). TdT was present. Immune studies suggested a T-cell phenotype (CD5+, CD7+); however, there was no rearrangement of the T beta-cell receptor gene. Surprisingly, the leukemia cells also expressed the CD13 myeloid antigen. Dual staining analysis showed co-expression of lymphoid and myeloid antigens on most cells. Based on these data and a review of previous reports we suggest that acute leukemia associated with the 5q- abnormality can occur in an immature stem cell resulting in a hybrid leukemia.