Homozygosity for 8pter----q22 in acute myeloblastic leukemia with t(8;21)(q22;q22)

A case of acute nonlymphocytic leukemia with homozygosity for the chromosome segment 8pter----8q22 is reported. A t(8;21)(q22;q22) translocation was associated with duplication of the derivative chromosome 8q- and absence of the normal chromosome 8. These rearrangements also yielded hemizygosity for 8q22----qter. This case shows that acquired hemizygosity and homozygosity do exist in leukemia as in solid malignant tumors.     

Recurrent t(16;17)(q22;p13) in aneurysmal bone cysts.

Aneurysmal bone cyst (ABC) is a benign bone lesion for which no previous cytogenetic data exist. We describe the finding of clonal chromosome aberrations in three tumors; two had a t(16;17)(q22;p13) as the sole anomaly, and the third had a del(16)(q22) as the only change. These findings show that somatic mutations contribute to the development of ABC and furthermore indicate that bands 16q22 and 17p13 may harbor genes of importance in this process.     

t(6;12)(q23;q13) and t(10;16)(q22;p11) in a phyllodes tumor of breast.

Cytogenetic analysis of short-term cultures from a phyllodes tumor showed clonal chromosome changes including t(6;12)(q23;q13) and t(10;16)(q22;p11). This is the first reported karyotype in this tumor type. We discuss the breakpoints of these translocations in relation to the involvement of possible candidate genes.     

Fluorescence in situ hybridization identifies inversion 16 masked by t(10;16)(q24;q22), t(7;16)(q21;q22), and t(2;16)(q37;q22) in three cases of AML-M4Eo

Bone marrow or peripheral blood from three patients had a t(10;16)(q24;q22), t(7;16) (q21;p13.1), and t(2;16)q37;q22), respectively. In all cases, fluorescence in situ hybridization confirmed an inv(16) masked by the translocation. The three patients were diagnosed with acute myelomonocytic leukemia and increased eosinophils. Because inv(16) has a favorable prognosis, identification of masked inv(16) will promote improved management of these cases. Therefore, all cases that have atypical rearrangement of chromosome 16 should be investigated for a possible inversion.     

Simultaneous occurrence of t(9;22)(q34;q11.2) and t(16;16)(p13;q22) in a patient with chronic myeloid leukemia in blastic phase

Coexistence of two specific chromosomal translocations in the same clone is an infrequent phenomenon and has only rarely been reported in hematological malignancies. We report a combination of t(16;16)(p13;q22), the Philadelphia translocation t(9;22)(q34;q11.2), and deletion of the long arm of chromosome 7 in a patient with chronic myeloid leukemia in blast phase. Monotherapy treatment with imatinib mesylate resulted in the disappearance of the Ph-positive clone, but with persistence of t(16;16) and del(7) in all of the metaphases examined. The case illustrates that, although imatinib mesylate can be an effective treatment in eradication of the BCR–ABL fusion gene cells, the occurrence of additional specific abnormalities in Philadelphia-positive leukemias may pose a significant therapeutic challenge.     

A novel t(16;20)(q22;p13) in polycythemia vera

We report a patient with polycythemia vera whose bone marrow cells carried a novel t(16;20)(q22;p13) as detected by karyotype analysis using G- and Q-banding techniques. The reciprocal translocation was confirmed by fluorescence in situ hybridization (FISH) using DNA libraries of chromosomes 16 and 20. To our knowledge, t(16;20)(q22;p13) has not been reported previously. The core binding factor beta (CBFbeta) gene located on 16q22 is known to be frequently involved in acute myelocytic leukemia. On the other hand, the 20p13 locus contains a gene encoding protein kinase CK2alpha, which is closely related to cell proliferation and cell cycle regulation. The t(16;20)(q22;p13) may be one of the cytogenetic aberrations in myeloproliferative disorders, and therefore, our observation warrants further studies on a possible involvement of the genes resulting from this translocation.     

Translocation (11;19)(q23;p13.3) associated with a novel t(5;16) (q13;q22) in a patient with acute myelocytic leukemia

A novel association of t(11;19)(q23;p13) and t(5;16)(q13;q22) was detected by G-banding and spectral karyotyping studies in an 18-year-old patient. While balanced t(11;19) has been often described in acute myelocytic leukemia (AML) French-American-British Cooperative Group subtypes M4 and M5, this patient was diagnosed with the variant AML-M4 with eosinophilia (AML-M4Eo), which is associated with abnormalities in 16q22 and has good prognosis. However, the patient relapsed after allogeneic transplant and died within 2 years of diagnosis, which suggests that the association of these two translocations correlates with a poor prognosis. This report expands the molecular basis of the variability in clinical outcomes and adds the novel t(5;16)(q13;q22) to the spectrum of chromosome 16q22 abnormalities in AML.     

Re-evaluation of GM2346 from a del(16)(q22) to t(4;16)(q35;q22.1)

Reassessment of the cytogenetics of a patient previously karyotyped as del(16)(q22) demonstrates the presence of a balanced translocation, t(4;16)(q35;q22.1). This patient should not be included in any future comparison involving the clinical features of patients with deletions of the long arm of chromosome 16.     

Novel chromosome 16 abnormality--der(16)del(16) (q13)t(16;21)(p11.2;q22)--associated with acute myeloid leukemia.

Inversion of chromosome 16 is a common feature of acute myeloid leukemia (AML) M4, while t(16;21), although also associated with AML, appears to be a separate entity. We present a patient with myelodysplastic syndrome (MDS) who transformed to AML-M1. The karyotype was normal at diagnosis; at 15 months, hematological evidence of transformation was present, and repeat cytogenetics showed a novel rearrangement of one chromosome 16. Two breaks had occurred; one in the short arm at 16p11, with translocation of the segment distal to this onto chromosome 21q, and the other in the long arm at 16q22 with subsequent deletion of the segment from 16q22-->qter. Fluorescence in situ hybridization (FISH) confirmed the abnormalities detected by cytogenetics and excluded involvement of the AML1 gene on 21q22. While the 16q22 breakpoint was at the usual site for the inv(16), the 16p11 was not. The patient is more characteristic of t(16;21) than inv(16), and adds to the spectrum of chromosome 16 abnormalities in AML.     

Nonrandom additional chromosome changes in acute nonlymphocytic leukemia with inv(16)(p13q22)

Five patients with acute nonlymphocytic leukemia and inv(16)(p13q22), all with additional chromosome changes, are reported. Three were diagnosed as having acute myelomonocytic leukemia (FAB-M4), and the other two as having acute monocytic leukemia (FAB-M5b). All five patients had abnormal eosinophils in the bone marrow at diagnosis. Two had a deletion of the long arm of chromosome #7, del(7)(q31), and a trisomy of chromosome #22. These changes have been reported frequently in acute nonlymphocytic leukemia with inv(16), but are extremely rare in leukemias with other specific rearrangements including t(9;22), t(8;21), and t(15;17). Our findings and review of the literature indicate that inv(16) is observed not only in acute myelomonocytic leukemia but also in acute monocytic leukemia, and that del(7q) and +22 are nonrandomly associated with inv(16) as additional abnormalities. No significant differences in the clinical features seem to exist between the patients with only inv(16) and those with inv(16) and additional chromosome changes, except for the lower white blood cell count in the latter group.     

Chronic myelomonocytic leukemia in a patient with a familial t(6;16)(q13;q22) translocation

A 75-year-old man with chronic myelomonocytic leukemia was found to have a constitutional t(6;16)(q13;q22) translocation, as did his healthy daughter. Chromosomal in situ hybridization studies of the daughter's lymphocytes did not indicate translocation-mediated interruption of the metallothionein gene cluster, at 16q22, although this locus has been reported to be involved in the eosinophilic variant of acute myelomonocytic leukemia. Lymphocytes from the daughter and from the patient's brother (who had a normal karyotype), had no increased fragility at 16q22. The findings do not provide evidence for an association between the familial chromosome abnormality and this patient's leukemia.     

inv(16)(p13q22) in chronic myelogenous leukemia in blast phase: a clinicopathologic, cytogenetic, and molecular study of five cases

Blast phase (BP) in chronic myelogenous leukemia (CML) frequently is accompanied by cytogenetic abnormalities in addition to t(9;22)(q34;q11.2). We describe 5 patients with CML in blast phase (CML-BP) in which t(9;22) and inv(16)(p13q22) were identified by conventional cytogenetics, with confirmation of BCR-ABL and CBFss-MYH11 by fluorescence in situ hybridization. The morphologic findings at the time of BP resembled de novo acute myeloid leukemia (AML) carrying inv(16)(p13q22), with abnormal eosinophils in the bone marrow and monocytosis in the peripheral blood in all cases. In 1 patient, inv(16)(p13q22) and abnormal eosinophils were detected in the bone marrow 2 months before CML-BP. The clinical course of these patients was similar to patients with CML-BP without evidence of inv(16)(p13q22). These cases illustrate that inv(16)(p13q22) is a form of cytogenetic evolution that rarely occurs in patients with CML at the time of BP. In this setting, unlike de novo AML, inv(16)(p13q22) in CML-BP is not associated with a favorable prognosis.     

5例伴有t(16;21)(p11;q22)急性白血病的临床和实验研究

目的：报告5例伴有t(16;21)(p11;q22)的急性白血病和其中1例的染色体涂染分析。方法：骨髓细胞24h培养后按常规方法制备染色体，采用R显带技术进行染色体核型分析，并以16号和21号整条染色体涂染探针对其中1例患者进行染色体涂染检测。结果：5例均显示t(16;21)(p11;q22),占15年来进行染色体检查的急性非淋巴细胞白血病患者总数的0．3％（5／1448）。5例均无白血病细胞吞噬其他血细胞现象。1例患者的染色体涂染分析证实了16号和21号染色体之间发生了相互易位。结论：t(16;21)是急性非淋巴细胞白血病中1种少见的非随机的染色体易位，代表了1种独特的白血病亚型。染色体涂染技术是比常规核型分析更为可靠的检测该易位的手段。     

Derivative (14)t(11;14)(q13;q32)t(11;14)(p11.2;p11.2): a novel unbalanced variant of the t(11;14)(q13;q32) translocation in mantle cell lymphoma

We report the case of a 62-year-old man who presented with splenomegaly, leukocytosis, anemia, and thrombocytopenia. Examination of the peripheral blood, bone marrow, and spleen revealed involvement by mantle cell lymphoma, with some blastoid features and an atypical phenotype. Spleen and bone marrow classical chromosome analysis followed by fluorescence in situ hybridization revealed a novel and unusual unbalanced variant of the t(11;14)(q13;q32) translocation, resulting in a complex derivative chromosome harboring the IGH/CCND1 fusion gene. This chromosome was designated as der(14)t(11;14)(q13;q32)t(11;14)(p11.1;p11.2).