Establishment and characterization of acute B-cell lymphocytic leukemia cell line showing (8;14) and (14;18) chromosome translocation

Cell line KHM-2B expressing two oncogene products, c-myc and bcl-2, was established from a patient with acute lymphocytic leukemia with an 8;14 and 14;18 chromosome translocation. Surface marker studies of the cell line showed that the cells were positive for HLA-DR, CALLA (CD10), B1 (CD20) and B4 (CD19), but negative for T11 (CD2). The fresh cells from peripheral blood of the patient had no surface immunoglobulins, whereas KHM-2B cells were positive for mu.lambda type surface immunoglobulin. A cytogenetic analysis of the cell line revealed two translocations, t (8;14) (q24;q32) and t(14;18)(q32;q21). Rearrangement of the c-myc and bcl-2 genes was detected by Southern blot analysis of the KHM-2B DNA. Northern blot analysis revealed production of c-myc and bcl-2 mRNAs. These results indicated that two oncogenes were activated by two translocations to immunoglobulin genes.     

The 8;21 chromosome translocation in acute myeloid leukemia is always detectable by molecular analysis using AML1

The AML1 gene was rearranged in leukemic cells with t(8;21)(q22;q22) or its variant, complex t(8;V;21) translocations from 33 acute myeloid leukemia (AML) patients. The AML1 rearrangement was also detected in three AML patients without t(8;21); two had a normal diploid karyotype, and one had a karyotype of 45,X, - X. The AML1 rearrangement in the t(8;21) breakpoint cluster region was not detected in leukemic cells with cytogenetic abnormalities other than t(8;21), or with normal diploidy obtained from 23 AML patients. Because leukemic cells of the five patients with complex t(8;V;21) translocations had a der(8)t(8;21) chromosome with a break in band 8q22 in common, the juxtaposition of the 5' side of AML1 to a predicted counterpart gene located in the breakpoint region of 8q22 may be an essential step in the leukemogenesis of AML with t(8;21). Our findings show that the 8;21 translocation, its variants, and the masked t(8;21) may all be detectable by the Southern hybridization method using the AML1 probes.     

Translocation breakpoints are clustered on both chromosome 8 and chromosome 21 in the t(8;21) of acute myeloid leukemia

The t(8;21)(q22;q22) is consistently associated with acute myeloid leukemia (AML) M2. Recent data have suggested that breakpoints on chromosome 21 are clustered within a single intron of a novel gene, AML1, just downstream of a region of homology to the runt gene of D melanogaster. In this report, we confirm rearrangement at the same location in at least 12 of 18 patients with t(8;21). Furthermore, we have isolated recombinant clones spanning the breakpoint regions on both the der(8) and the der(21) from one patient. By using a chromosome 8 probe derived from these clones, we show that t(8;21) breakpoints are also clustered on chromosome 8.     

Clinical and cytological features of acute myelogenous leukemia with 8; 21 chromosome translocation

Eight cases of acute myelogenous leukemia with (8; 21) translocation were reported. As recently reported, they showed following features: M2 morphology in FAB classification (all 8 patients), abnormal granulocyte maturation, i.e. large granules and pseudo Pelger-Huet forms (5), Auer rods (8), occasional eosinophilia (2), frequent loss of one sex chromosome (5), the low neutrophil alkaline phosphatase activity (5), and tumor formation (one). Both CD13 and CD33 antigens were expressed on smaller number of leukemic cells than the other AML (M2) cells, whereas CD34 and HLA-DR antigens were expressed on higher number of cells. Interestingly CD19 antigen was detected on a small to large population of tumor cells from four out of six patients. Despite the high remission rate, many of them relapsed within one year. More intensive postinduction and maintenance therapy should be considered for those patients.     

Establishment of a human myeloid cell line with trisomy 8 derived from overt leukemia following myelodysplastic syndrome

A human myeloid cell line with trisomy 8 was newly established from overt myelogenous leukemia arising in myelodysplastic syndrome. The cells of this cell line showed immature myelocyte characteristics. The karyotype retained trisomy 8. This cell line could improve understanding of the pathophysiology of myelogenous leukemia with trisomy 8.     

T(8;21) with a phenotype of chronic myeloid leukemia

A myeloproliferative disorder having the phenotype of chronic myeloid leukemia (CML) with t(8;21) is reported. Neither t(9;22) nor a DNA rearrangement in the bcr region was detected. The presence of t(8;21), in contrast with previous experience, does not appear to prevent full maturation of the granulocytic series.     

Tetraploidy or near-tetraploidy clones with double 8;21 translocation: a non-random additional anomaly of acute myeloid leukemia with t(8;21)(q22;q22)

We report on 6 patients with tetraploidy or near-tetraploidy acute myeloid leukemia (AML) with double t(8;21) (q22;q22) and review the literature on cases with the same cytogenetic abnormalities. Some common features were revealed by this analysis.     

t(8;21) breakpoints on chromosome 21 in acute myeloid leukemia are clustered within a limited region of a single gene, AML1.

The t(8;21)(q22;q22) translocation is a non-random chromosomal abnormality frequently found in patients with acute myeloid leukemia (AML) with maturation (M2 subtype). We report here the cloning of a gene, named AML1, on chromosome 21 that was found to be rearranged in the leukemic cell DNAs from t(8;21) AML patients. The breakpoints in 16 out of 21 patients were clustered within a limited region of AML1, and detailed analysis in 3 patients revealed that the breakpoints occurred in the same intron of the gene. Sequencing of cDNA clones identified a long open reading frame encoding a 250-amino acid protein. Northern blot analysis detected four constant mRNA species in t(8;21) leukemic and normal cells; the largest species was more abundant in the leukemic cells than in normal cells. In addition, two mRNA species limited to the leukemic cells were found. These findings indicate that the AML1 gene may be involved in neoplastic transformation of AML with the t(8;21) translocation.     

Establishment of a new peroxidase-positive human myeloid cell line, PL- 21

A myeloid cell line, designated PL-21, was established from the peripheral blood of a patient with acute promyelocytic leukemia. The PL- 21 cell line grew in single-cell suspension, with a doubling time of 48- 64 hr, and consisted of promyelocytes with fine immature nuclei and prominent azurophilic granules in the cytoplasm. PL-21 cells were positive for peroxidase, naphthol AS-D chloroacetate esterase, and Sudan Black B staining. Under the usual culture conditions, a small proportion of these cells differentiated into mature granulocytes, and this differentiation was enhanced by the addition of dimethyl sulfoxide in the culture medium. PL-21 cells had receptors for the Fc portion of IgG and complement, intracytoplasmic lysozyme and phagocytic activity, but lacked Epstein-Barr virus-associated nuclear antigen. Chromosome analysis of this cell line revealed a human male polyploid karyotype with 13q+ and double minute chromosomes. This new myeloid cell line may provide useful material for the study of proliferation and differentiation of human leukemia cells.     

A new chromosome translocation (3;21) in M2 acute lymphocytic leukemia

High-resolution chromosome banding studies were carried out on leukemic cells from a young patient with acute nonlymphocytic leukemia (ANLL), M2 of the FAB classification. A new chromosomal abnormality involving a translocation between chromosomes 3 and 21 was observed, i.e., t(3;21)(p14;q22). A complete remission was never obtained in spite of aggressive chemotherapy and the patient died 8 months after diagnosis.     

Characterization of a factor-dependent acute leukemia cell line with translocation (3;3)(q21;q26).

A strictly factor-dependent cell line (UCSD/AML1) was established from a patient with the syndrome of multilineage acute leukemia with high platelets. The patient's cells and the cell line karyotype were 45,XX,-7,t(3;3)(q21;q26), typical of the syndrome of acute leukemia with high platelets. The cell line expresses CD34, CD7, TdT, and myeloid (CD13, CD14, CD33) and megakaryocyte/platelet (CD36, CD41, CD42b, CDw49b) antigens. In short-term culture, UCSD/AML1 cells proliferate in response to interleukin-3 (IL-3), IL-4, IL-6, macrophage colony-stimulating factor (M-CSF), and granulocyte-macrophage CSF (GM-CSF), but not IL-1, IL-2, IL-5, or G-CSF. In long-term culture, proliferation can be sustained by GM-CSF, IL-6, or M-CSF. When maintained in GM-CSF, a small percentage of cells form multinucleated megakaryocyte-like giant cells. Culture with GM-CSF combined with IL-6, but not with IL-6 alone, increased giant cell formation fourfold to sevenfold. IL-6 alone or in combination with GM-CSF increased expression of platelet-related antigens. In contrast, culture with phorbol ester induced formation of macrophage-like cells. UCSD/AML1 is the first human acute nonlymphocytic leukemia cell line established from a patient with an acute leukemia syndrome associated with a specific chromosome abnormality.     

Testicular infiltration in acute myeloid leukemia with complex karyotype including t(8;21)

Testicular infiltration is a well-known complication in acute lymphoblastic leukemia. In acute myeloid leukemia (AML), it has rarely been described and preferably occurred in cases with myelomonocytic or monoblastic differentiation. We report on a patient with AML with complex karyotype including translocation t(8;21) who presented with testicular infiltration at the time of his third bone marrow relapse. Cytological analysis of the specimen showed infiltration with blasts displaying the typical morphology of AML with translocation t(8;21) and comparable to those detected in the bone marrow. Fine needle aspiration cytology might suffice in these cases and should be performed if testicular involvement is suspected.