The chromosomes in hematology

t(12;21): a new recurrent translocation in acute lymphoblastic leukemia

A t(12;21)(p11-p12;q22) was detected by chromosome painting in three patients with acute lymphoblastic leukemia (ALL) among eight ALL cases with 12p- abnormalities. The three leukemias had similar immunophenotypes (DR+, CD10+, CD19+). Fluorescence in situ hybridization (FISH) experiments using YAC clones from 21q21-q22 were performed to better localize the breakpoint on chromosome 21. This breakpoint was localized to 21q22.2 in one patient. Although only one case of ALL with t(12;21) has been reported previously, the present results suggest that t(12;21) is a recurrent translocation in ALL.

Isolation and characterization of a spontaneously arising long-lived line of human keratinocytes (NM 1)

The long-lived keratinocyte line, NM 1, was isolated from the epidermis of a pool of foreskins obtained from apparently normal neonates at the time of circumcision. Cultures were initiated in Dulbecco's minimal essential medium containing 20% fetal bovine serum, 0.4 micrograms/ml hydrocortisone, 10(-9) M cholera toxin, and 10 ng/ml epidermal growth factor using mitomycin C-treated 3T3 cells as a feeder layer. Unlike normal keratinocytes which survive for only 150 generations these cells have been in culture for more than a year and have been carried for more than 400 doublings. The cells seem to follow a pathway of growth and differentiation that is very similar to normal keratinocytes. Cytokeratin fibrils, intercellular attachments, and cornified envelopes were observed. The keratin polypeptides isolated from the NM 1 cells were similar to those previously described in normal cultured cells; the presence of profilaggrin and involucrin was demonstrated by sodium dodecyl sulfate electrophoresis and immunoblotting with monoclonal antibodies specific to these proteins. The NM 1 cells showed a reduced dependency on 3T3 feeder cells but did not form tumors when placed into athymic nude mice. Screening of the cells for SV40, BK, HPV 16, and HPV 18 viruses was negative. The NM 1 cells showed trisomy of chromosome 8. The long-lived nature of these cells makes them a valuable model for studying growth and differentiation of keratinocytes.

Chromosome and cell culture studies in eosinophilic leukaemia

A cytogenetic analysis was carried out on bone marrow cells from 11 patients who presented with hypereosinophilia and the clinical features of the idiopathic hypereosinophilic syndrome. One of these patients was found to have trisomy 8 affecting the myeloid series, including eosinophils. In this patient, marrow eosinophils also showed asynchrony of nuclear-cytoplasmic maturation, and there were increased numbers of myeloid progenitor cells in the blood. Six months later, blast cell transformation occurred, and he died soon afterwards. These findings show that abnormalities in the karyotype of bone marrow cells and culture of blood progenitor cells may help to identity eosinophilic leukaemia among patients who present with features of the idiopathic hypereosinophilic syndrome.

The 5q-anomaly

A deletion of the long arm of chromosome #5 (5q-) occurs nonrandomly in human malignancies. As a rule, the deletion is interstitial; the distal breakpoint by conventional techniques is usually in band q32, the proximal breakpoints in q12 or q14. Variant breakpoints occur in less than 10% of all cases. As the sole anomaly, 5q- is characteristically found in refractory anemia with or without excess of blasts. It can occur as the sole anomaly in de novo or secondary acute nonlymphocytic leukemia, but is usually accompanied in those disorders by other chromosome changes that are also nonrandomly distributed. In addition, it can be found in lymphoproliferative disorders, and occasionally, also in solid tumors. The 5q- myelodysplastic syndrome typically occurs in older age groups, particularly in females. Characteristic features are macrocytic anemia, normal or elevated platelets in the presence of megakaryocytic anomalies, and a mild clinical course. In cases with 5q- only, transformation into ANLL occurs rarely. Additional chromosome anomalies and male sex are prognostically unfavorable signs. Sex ratio is also at the disadvantage of females in de novo 5q- ANLL, and the latter disorder can occur without being preceded by a myelodysplastic phase. A myelodysplastic phase usually precedes 5q- secondary leukemia, in males as well as in females, and additional chromosome anomalies, especially of chromosome #7, are almost invariably present in those cases. We conclude that 5q- is the most frequently occurring single chromosome anomaly in secondary leukemia. Furthermore, the resemblance between de novo and secondary 5q- MDS and ANLL is striking; clinically, as well as cytogenetically, they are indistinguishable, suggesting that all de novo cases may be due to environmental (chemical) carcinogens. Response to treatment and prognosis are very poor with current therapeutic regimens in de novo as well as in secondary 5q- ANLL. Morphologically, these ANLLs fall into all FAB categories. There is considerable evidence to show that the 5q- anomaly occurs in a myeloid precursor stem cell. The occasional occurrence in lymphoid malignancies, of B cell as well as T cell type, suggests that, as in Ph-positive disorders, a common progenitor stem cell may be affected in 5q- also. The 5q- lymphoid malignancies, however, are much more rare; it is not clear at the present time whether or not a 5q- counterpart of Ph-positive ALL exists, and mixed lymphoid-myeloid 5q- disorders have not yet been documented.(ABSTRACT TRUNCATED AT 400 WORDS)

Loss of the Y chromosome in acute myelogenous leukemia: a report of 13 patients

Thirteen male patients with acute myelogenous leukemia who, on bone marrow chromosome analysis, were missing all or part of the Y chromosome were treated at this institution between 1975 and 1983. Giemsa-banding techniques were performed in 12 cases. Twelve showed -Y in at least 80% of bone marrow metaphases, and one patient had 25% 46,XYqh-. The loss of the Y chromosome was the sole karyotypic abnormality in nine patients, and the remaining four had additional chromosome changes. The peripheral blood lymphocytes were diploid in all except three cases, where no mitotic cells were recovered. The median age was 55 years, eight patients had acute myelogenous leukemia (M2) and five acute myelomonocytic leukemia (M4). Six patients (46%) had an antecedent hematologic disorder. Eleven patients received standard induction combination chemotherapy. Complete remission was achieved in seven patients (63%). Remission bone marrow chromosome analysis showed 100% 46,XY in all seven cases. The median durations of complete remission and survival were 10 months and 12 months, respectively. The review suggests that -Y is a consistent, although uncommon, chromosome marker in acute myelogenous leukemia, associated with an aggressive clinical course and intermediate prognosis.

Multiple myeloma terminating in acute eosinophilic leukemia

A 71-year-old woman with multiple myeloma was successfully managed for 8 years with melphalan (total dose 2056 mg). She developed a refractory anemia (myelodysplastic state), which terminated in acute eosinophilic leukemia. This form of acute leukemia, induced by chemotherapy, appears to be very rare. The cytogenetic changes, including 5q- and monosomy 7, were similar to those observed in other patients with acute nonlymphocytic leukemia as a secondary malignancy following treatments of other primary tumors.

Morphologic, immunologic, enzymehistochemical and chromosomal analysis of a cell line derived from Hodgkin's disease. Evidence for a B-cell origin of Sternberg-Reed cells

Cell lines derived from Hodgkin's disease may provide a clue to the nature of Sternberg-Reed cells. In the current study, the establishment of an Epstein-Barr-virus-negative lymphoblastoid cell line, derived from the pleural fluid of a patient with the nodular sclerosis type of Hodgkin's disease, is described. The morphologic and immunologic cell marker findings indicate that this cell line is derived from Sternberg-Reed cells. The immunologic findings and a chromosomal analysis are in agreement with a B-lymphocyte origin of these cultured cells. Extrapolation of the results to Hodgkin's disease in vivo would indicate that Hodgkin's disease, like most non-Hodgkin's lymphomas, is the result of B-cell proliferation.

Translocation 1;7 in dyshematopoiesis: possibly induced with a nonrandom geographic distribution

Eight patients with various hematologic disorders had an identical chromosomal aberration in their bone marrow or unstimulated peripheral blood, a translocation t(1;7) interpreted as t(1;7)(p11;p11). The translocation chromosome replaced one normal chromosome #7; therefore, the karyotype of the abnormal cells was trisomic for 1q and monosomic for 7q. Including four cases from the literature, a total of 12 patients (4 women, 8 men) with this translocation are known at the moment. The translocation does not seem to be associated with a specific disorder, but almost all patients had a preleukemic syndrome during some stage of their disease. It is very remarkable that 11 of the 12 patients lived in the Netherlands, and 7 patients had a history of iatrogenic exposure to alkylating agents or irradiation; one patient was a radiation worker and another one had a history of toxic exposure to chloramphenicol. It is suggested, therefore, that the t(1;7) is a possibly induced chromosomal aberration with a clearly nonrandom geographic distribution.

Oncogenes: clues to carcinogenesis

Recent applications of recombinant DNA techniques in cancer research led to the detection of cellular genes with potential transforming activity, called oncogenes (c-onc). Regularly they seem to be involved in normal cell differentiation and proliferation: a number of oncogene-encoded proteins specifically phosphorylates tyrosine, a key reaction in growth control. Certain human tumors exhibit activated forms of these genes and DNA fragments isolated from these neoplasms transform nonneoplastic cells (transfection assay). Oncogenes were first discovered and defined in a number of retroviruses; these viral oncogenes (v-onc) are thought to have been derived from the cellular oncogenes (c-onc). By integration of the v-onc genes into the host genome acute neoplastic transformation of the cell may occur. Several modes of oncogene activation are discussed that lead either to an increased dosage of gene product or to the formation of an altered gene product. The localization of oncogenes in the human genome near the breakpoints of specific chromosome aberrations involved in various neoplasms like Burkitt lymphoma and several leukemias emphasizes the importance of these genes in carcinogenesis.

Human and mouse cellular myc protooncogenes reside on chromosomes involved in numerical and structural aberrations in cancer

A molecular clone of viral myc (v-myc), the oncogene of avian myelocytomatosis virus, MC29, detected homologous human, mouse, and Chinese hamster cellular myc (c-myc) sequences by Southern filter hybridization. A v-myc probe, containing sequences from the 3' domain of the gene, hybridized to single human HindIII and mouse EcoRI genomic DNA fragments of the cellular myc genes whose segregation could be followed in interspecies somatic cell hybrids. Human c-myc segregated concordantly with the enzyme marker glutathione reductase and with a karyotypically normal chromosome 8. A rearrangement of human c-myc was observed in Burkitt's lymphoma cells possessing the t(8;14) translocation. These results suggest that human c-myc is located close to the breakpoint on chromosome 8 (q24) involved in the t(8;14) translocation. The mouse c-myc gene segregated concordantly with chromosome 15 in mouse-Chinese hamster cell hybrids. These gene assignments are noteworthy, as structural and numerical abnormalities of human chromosome 8 and mouse chromosome 15 are associated frequently with B-cell neoplasms.

Fluorodeoxyuridine synchronization of bone marrow cultures

A method for synchronization of bone marrow cells with fluorodeoxyuridine (FdU) is presented and compared with methotrexate (MTX) synchronization. FdU has the advantage of not requiring cell washing for release of the DNA synthesis block and was found to be more beneficial for bone marrow cultures because it generally produced a higher mitotic yield and was less damaging to chromosomes. Late-replication banding, produced after releasing the FdU block with bromodeoxyuridine (BrdU), indicated that cells in midsynthesis at the time of the block release were those that showed the most increase in chromosome length and the most improvement in the quality of the metaphase spread. Therefore, because bone marrow cells have a longer cell cycle time than stimulated lymphocytes, a minimum of 7-8 hr culture after release of the block is recommended to give optimal results. It was also found that, to increase the yield of mitoses, at least 6-8 hr of growth was necessary before the addition of either of these synchronizing agents.

Cytological types of mitoses and chromosome abnormalities in acute leukemia

In order to determine the nature of the cells in mitosis in acute leukemia, a parallel study was conducted by cytological and cytogenetic methods on the same marrow and blood samples. On direct marrow examination, erythrocyte precursors in mitosis are usually observed but ordinarily disappear following in vitro culture. In APL (M3) characterized by t(15;17) translocation, the comparison between the proportions of the different categories of cells in mitosis and of karyotypically normal and abnormal cells suggests that erythroblasts do not belong to the leukemic clone. An analogous situation is observed in AML (M2) with t(8;21) and in monocytic leukemia (M5) with chromosome abnormalities. Erythroleukemia could be divided into two categories, one with chromosome abnormalities and persistence of erythroblast mitoses after culture, and another with no detectable chromosome abnormality and with disappearance of erythroblast mitoses following culture. Other examples of blood malignancies demonstrate the importance of the method used in determining which cell categories belong to the leukemic clone. An interpretation of the results in terms of commitment 'level' of the involved stem cells and a distinction between 'primary' and 'secondary' chromosome abnormalities is proposed.

Establishment and characterization of a human EBV-negative B cell line (MN 60)

A permanent cell line, MN 60, was established from the peripheral blood of a patient with an acute lymphoblastic leukemia (ALL) classified morphologically as being of the L3 type. Cell growth started rapidly in vitro and no feeder cells were needed. Cells of the MN-60 line were identical to the original leukemic cells with respect to surface immunoglobulin (Ig) expression and karyotype, including the presence of four marker chromosomes [1q+, 6q-, t(8;14)]. Continuous proliferation was maintained in stationary suspension culture with a doubling time of 25 h. The cells were tumorigenic in athymic nude mice and had the capacity to form colonies in semi-solid medium in vitro. Monoclonal surface Ig (mu lambda) was demonstrated whereas no cytoplasmic immunoglobulin could be demonstrated. The MN-60 cells were Epstein-Barr virus (EBV) negative as evidenced by EBNA tests and by nucleic acid hybridization studies. The cells expressed HLA-A-C, HLA-DR. beta 2-Microglobulin and cALL, but not Fc gamma. C3, sheep and mouse red blood cell receptors. No reactivity was found with anti-glycophorin A or the anti-BL 38.13 monoclonal antibody. Cell growth was retarded in the G0/G1 phase of the cell cycle after incubation with leukocyte interferon, hydrocortisone, phorbol myristate acetate and dimethyl sulphoxide.