Pseudodiploid Clone Research Articles

Peculiarities of chromosomal abnormalities in bone marrow cells at diagnosis of multiple myeloma

The results of cytogenetic and i-FISH investigations in bone marrow cells of 99 patients at diagnosis of multiple myeloma are presented. Metaphase chromosomes slides were prepared according to the generally accepted methods, after 24 and 96 h of cultivation in nutrient medium without stimulation. According to the clone structure, karyotypes with normal and normal/near tetraploid clones were dominated (78.3 %). With regard to the ploidy level, pseudodiploid clones were recorded more often (12.1 %), hyperdiploidy was revealed in 7.2 % cases. Among the structural rearrangements, the deletions were dominated, namely, 12.1 % were found by cytogenetic study and 34.5 % – by- i-FISH. The structural rearrangements were shown to involve chromosomes 13 and 17 (6 % and 1.2 %, respectively) more frequently using standard cytogenetic study, while del(17p) and del(13q) (24.1 % and 15.5 %, respectively) – by- i-FISH. Atypically low was a frequency of translocations involving the gene IgH (14q32) (1,8 %). Unusual distribution of the signals with the involvement of IgH gene indicates an additional mechanism for the abnormal clone formation. By the cytogenetic analysis data, 8.9% cases, by the i-FISH data, 34.5 % cases and summarizing both methods – 52.2 % cases, were referred to the group of adverse genetic prognosis during the course of disease.

Clonal evolution in UKE-1 cell line leading to an increase in JAK2 copy number

Clonal evolution in UKE-1 cell line leading to an increase in JAK2 copy number

Phase II Study of Combination of hyperCVAD with Dasatinib in Frontline Therapy of Patients with Philadelphia Chromosome (Ph) Positive Acute Lymphoblastic Leukemia (ALL)

Background: Combination of cytotoxic chemotherapy with imatinib has improved the outcome for patients with Ph+ ALL with durable remissions in some patients without an allogeneic stem cell transplant. The dual Src and Abl inhibitor dasatinib has significant clinical activity in patients with imatinib-resistant lymphoid blast phase CML and Ph+ ALL.Methods: In this phase II trial, patients with newly diagnosed Ph+ ALL receive dasatinib 50 mg po bid (or 100 mg daily) for the first 14 days of each of 8 cycles of alternating hyperCVAD and high dose cytarabine plus methotrexate. Patients (pts) in CR continue to receive maintenance dasatinib 50 mg po bid (or 100 mg daily) and vincristine and prednisone monthly for 2 years followed by dasatinib indefinitely. Minimal residual disease (MRD) monitoring is conducted and patients may receive early and late intensifications depending on their MRD status.Results: To date 22 pts with untreated Ph+ ALL and 6 pts with 1 prior cycle of chemotherapy (before Ph+/BCR-ABL+ status was known) have received a median of 6 cycles (range 1–8); 9 pts are receiving maintenance in CR. Median age is 52 years (range 21 – 79); 16 pts were older than 50 years. Median WBC at diagnosis was 20.5 ×109/L (range, 1.6 –275 × 109/L). 5 pts had CNS involvement at presentation. All pts are evaluable for assessment of response; 26 (93%) achieved CR after 1 cycle. Two pts died before response assessment from infections; in both pts, bone morrow exam on day 14 showed no detectable disease. Twenty one of 26 (81%) evaluable pts achieved cytogenetic (CG) CR after 1 cycle; 2 had a major CG response (5% and 15% Ph+), 2 had insufficient metaphases, and one is unknown (no CG exam on day 21 marrow); 1 pt developed a pseudodiploid clone. To date, 14 pts (50%) have achieved complete molecular remission (CMR) and 5 (18%) have achieved a major molecular response (MMR) at a median of 10 weeks from initiation of treatment (range 2 – 46 weeks). MRD assessment by flow cytometry is negative in 22 (85%) pts at a median of 3 weeks (range, 2–17 weeks). The median time to neutrophil and platelet recovery for cycle 1 is 18 and 23 days and for subsequent cycles is 15 and 20 days, respectively. Grade ≥3 toxicity has included 13 episodes of bleeding (8 GI, 2 GU, 1 soft tissue hematoma and 2 subdural hematomas), 3 episodes of pleural effusions, infections, diarrhea, hypophosphatemia, hypocalcemia, elevated transaminases, and reversible rise in creatinine unrelated to treatment. With a median follow up of 10 months (range, 2–21), 21 pts are alive and 18 are in CR; 2 died at induction, 3 pts died in CR; 1 from an unrelated cardiac event and 2 from infections. 5 pts have relapsed (response durations were 54, 48, 47, 32, and 22 weeks) and 2 of them have died. In 2 pts morphological relapse was preceded by flow and molecular relapse. Four relapsed pts developed new ABL mutations (3 T315I and 1 F359V). One patient has undergone an allogeneic stem cell transplant.Conclusions: The combination of hyperCVAD with dasatinib is effective in achieving molecular remissions in patients with Ph+ ALL. There is a high incidence of T315I ABL mutation among the relapsed patients.

Aggressive Osteoblastoma: A Case Report Involving a Unique Chromosomal Aberration

Osteoblastomas are rare bone-producing neoplasms that generally occur in the young and can be misdiagnosed as an osteosarcoma if correlation with clinical history, radiology, and histology is not carefully considered or if the several variants of osteoblastoma are not recognized. These variants lie on a morphologic spectrum between conventional osteoblastoma and osteosarcoma. Aggressive osteoblastoma is one such subtype. As the name implies, the histologic features of aggressive osteoblastoma may appear malignant, and its biologic behavior may separate it from conventional osteoblastoma. We report a case of aggressive osteoblastoma occurring in the femoral diaphysis of a 12-year-old girl; this osetoblastoma was dyssynchronous from the radiologic appearance and a diagnostic challenge. Cytogenetic evaluation of the neoplasm revealed a pseudodiploid clone with a balanced translocation involving chromosomes 4, 7, and 14. Using the premise that cytogenetics might be useful as a diagnostic tool for a more specific classification, we reviewed the literature in order to compare our findings with known chromosomal aberrations.

Secondary near-tetraploidy with double der(15)t(15;17) in acute promyelocytic leukemia in relapse

Tetraploidy or near-tetraploidy is a rare cytogenetic abnormality in acute myelocytic leukemia. We report here a case of acute promyelocytic leukemia that showed near-tetraploidy with double der(15)t(15;17) the leukemia relapsed. At diagnosis, cytogenetic analysis failed to reveal any karyotypic abnormality; however, a promyelocytic leukemia–retinoic acid receptor α ( PML/ RARA) fusion transcript of the bcr3-type was detected with reverse transcriptase-polymerase chain reaction analysis, and a single PML/RARA fusion signal was observed with fluorescence in situ hybridization analysis. At the first relapse, the majority of leukemic cells showed pseudodiploid karyotypes with der(15)t(15;17), as well as additional chromosomal abnormalities, and exhibited a single PML/RARA fusion signal. A small fraction of leukemic cells, however, showed near-tetraploid karyotypes with double der(15)t(15;17), as well as some additional chromosomal abnormalities in common with the pseudodiploid clones, and exhibited double PML/RARA fusion signals. At the second and third relapses, leukemic cells with near-tetraploidy and double PML/RARA fusion signals became predominant. The PML/RARA fusion transcript of the bcr3 type was also observed at each relapse. In addition, Southern blot analysis of the RARA gene at diagnosis and at the second relapse showed a common rearranged band. Notably, giant, bizarre, and hypogranular promyelocytes expressing CD2, CD34, and HLA-DR appeared at the first relapse and became predominant at the second and third relapses. These observations indicate that the APL cells with near-tetraploidy and double der(15)t(15;17) clonally evolved from the pseudodiploid leukemic cells and exhibited the bizarre morphology and aberrant surface immunophenotypes.

Regulation of a distinctive set of genes in glucocorticoid-evoked apoptosis in CEM human lymphoid cells.

Gene expression was evaluated in clones of the acute lymphoblastic leukemic cell line CEM that were sensitive or resistant to apoptosis evoked by the glucocorticoid, dexamethasone (Dex). Founding clones CEM-C7 (glucocorticoid sensitive) and CEM-C1 (glucocorticoid resistant) were subcloned to maximize uniformity of each population studied. Among subclones of C1, our original pseudodiploid clone of glucocorticoid-resistant cells, we found a high proportion of hyperploid clones. Most C1 subclones were glucocorticoid resistant but two C1 subclones were found to be revertants to glucocorticoid sensitivity. Glucocorticoid receptor content of the C1 subclones varied almost 5-fold but higher quantity of receptors did not guarantee steroid sensitivity. Gene expression analysis was carried out on microchips containing representations for approximately 12,600 human genes. When a group of four subclones from C1 (three glucocorticoid-resistant and one glucocorticoid-sensitive revertant) were compared with the glucocorticoid-sensitive subclone CEM-C7-14 for basal gene expression, the four C1 subclones clustered closely and far from C7-14. Thus, basal gene expression in the C1 subclones differed for a large number of genes from that in the C7 subclone. Reversion to glucocorticoid sensitivity did not cause a major shift in basal gene expression to a more C7-like state. Three clones (one revertant glucocorticoid sensitive from C1 subclone, one C7 sensitive subclone, and one C1 glucocorticoid-resistant subclone) were compared for the genes regulated by treatment for 20 hours with 10(-6)M Dex. This interval brings the cells to a point just before the onset of apoptosis. We tested the hypothesis that a distinctive set of genes would be regulated in the glucocorticoid-sensitive clones. This proved to be so. In three experiments, at our chosen levels of discrimination, 39 genes were consistently induced > or = 2.5-fold and 21 genes were consistently reduced > or = 2-fold in glucocorticoid-sensitive clones but not in the glucocorticoid-resistant clone. The glucocorticoid-resistant clone showed induction or reduction of 88 genes different from those regulated in the glucocorticoid-sensitive clones. These data support our hypothesis and further show that the glucocorticoid-resistant clone is capable of responding to steroid but with a different set of genes. We propose that a general metabolic switch accounts for the alteration.

Spectral karyotyping of Werner syndrome fibroblast cultures

Fibroblast cultures from two Werner syndrome patients were analyzed by spectral karyotyping. There were multiple, pseudodiploid clones in both cultures, mostly marked by random balanced reciprocal translocations. One of the cultures contained a clone with three-way exchanges involving chromosomes 2, 3, and 16. Duplication-deficiencies were exceptional, as were completely normal metaphases. The most frequent breakpoint occurred at 16q22 which corresponds to FRA16B, possibly reflecting difficulties of WS cells in replicating AT-rich repetitive DNA structures. Both cultures ceased proliferation after eight in vitro passages, but a single clone with exceptional growth potential emerged in one of the senescing cultures. Due to its identical translocations, the derivation of this near tetraploid clone (with tetrasomy for all autosomes except chromosomes 4 and 6) could be traced to the most prevalent pseudodiploid clone of the parental mass culture. Our study confirms the existence of variegated translocation mosaicism as the cytogenetic hallmark of WS fibroblast cultures and suggests that tetraploidization in combination with certain chromosome rearrangements and selective chromosome dosage may overcome the severely limited in vitro lifespan of WS fibroblasts.

Importance of DNA damage in the induction of apoptosis by ionizing radiation: effect of the scid mutation and DNA ploidy on the radiosensitivity of murine lymphoid cell lines

Purpose: To study the effects of the murine scid mutation and DNA ploidy on the susceptibility of lymphoid cell lines to induction of apoptosis by ionizing radiation and thereby to determine whether DNA lesions are critical initiators of apoptosis. Materials and methods: Sensitivity to killing and rapidity of induction of apoptosis following gamma-irradiation or DNA-associated 125I decays were compared in pre-B and pre-T cell lines derived from wildtype mice and from mice homozygous or heterozygous for the scid mutation. Effects of differences in DNA ploidy on the same endpoints were studied using pseudo-diploid and-tetraploid clones of a murine pre-T cell line. Results: Pairs of pre-B- and pre-T cell-derived lines that expressed wild-type p53 and underwent rapid interphase apoptosis after irradiation were identified. In both cases, the scid homozygous cell lines were more sensitive to killing, suggesting that DNA repair capability influences susceptibility to induction of apoptosis. Increasing DNA ploidy in a cell line that undergoes rapid interphase apoptosis produced a corresponding increase in the number of DNA lesions required to produce a lethal event; again consistent with DNA being the target for radiation action. Conclusion: DNA damage is an important, if not the sole, initiator of external beam ionizing radiation-induced apoptosis.

Cytogenetics in Multiple Myeloma: A Multicenter Study of 24 Patients with t(11;14)(q13;q32) or Its Variant

Twenty-two patients with multiple myeloma (MM) with a classical t(11;14)(q13;q32) and two complex variants also involving 11q13 and 14q32 regions are reported. We show that t(11;14) (q13;q32) is predominantly noticed in stages II and III and never in stage I patients. Translocation (11;14)(q13;q32) is predominantly observed in hypodiploid or pseudodiploid clones associated with total or partial monosomy of chromosome 13 and additional structural changes in chromosome 1. These translocations may be discovered not only in standard cultures (24–48 hours) without stimulation, but also in cytokine-stimulated cultures (granulocyte macrophage colony-stimulating factor and interleukin 6). The t(11;14)(q13;q32) as a primary or secondary event in MM is discussed, because, in one patient, it was only discovered at relapse.

Pigmented choroid plexus carcinoma: A cytogenetic and ultrastructural study

A pigmented choroid plexus carcinoma was studied. The pigment was Fontana-positive, and the neoplastic cells focally expressed melanosomal marker HMB45 and contained probable aberrant melanosomes. The tumor was composed of two pseudodiploid clones, having the karyotypes 46,XY,in v(4)(q 12q35), t(6;15)(g21;q22),inv(7)(p 11.2822), t(19;22)(q13.4; q11.2)(15)l46,XY, t(4;14)(q31.1; p11.2),t(12;13)(p11.1;q34)(6]. The available data seem to indicate that rearrangements of 7p11–12, 9q11–12, 15822, and 19813.4 may playa role in the development of choroid plexus carcinomas.

Karyotypic features of malignant tumors of the nasal cavity and paranasal sinuses.

Cytogenetic analysis of short-term cultures from 6 tumors of the nasal cavity and paranasal sinuses--one esthesioneuroblastoma, 2 adenocarcinomas and 3 squamous-cell carcinomas (SCC)--revealed clonal chromosome aberrations in all cases. The esthesioneuroblastoma had a complex hyperdiploid karyotype. None of the aberrations was similar to those previously described in short-term cultures or established cell lines from esthesioneuroblastomas. The 2 adenocarcinomas had complex karyotypic changes, which in both cases included rearrangements of bands 9p22 and 14q11. One SCC had 5 unrelated pseudodiploid clones, 1 displayed a highly complex karyotype, including rearrangement of band 11q13, and 1 had simple karyotypic changes with loss of 6q material and gain of 3q. These findings are similar to those described in head-and-neck SCC at other sites.

Clonal evolution of an immunoblastic type non-Hodgkin's lymphoma with der(6)t(1;6)(q11;p11) as its primary cytogenetic abnormality

Recurrent pleural effusions from a 45-year-old man who was diagnosed as having non-Hodgkin's lymphoma of immunoblastic type were studied cytogenetically. The majority of the metaphases were tetraploid, but there were also lymphoma cells observed with pseudodiploid chromosome constitutions. Cytogenetic analysis by G-banding revealed the existence of at least two cell populations. The karyotype of the minor pseudodiploid clone, which exhibited partial trisomy of 1q11qter and monosomy of 6p11pter as sole abnormalities, was 46,XY,der(6)t(1;6)(q11;p11). The karyotype of the major clone was 92,XXYY, −1,der(6)t(1;6)(q11;p11)x2, +9. The ancestral diploid clone, carrier of the balanced translocation involving chromosomes 1 and 6, was not observed even in the first pleural effusion harvest. The high proportion of tetraploid cells in the recurrent effusions was an indication that these cells were favorably selected in the environment of the somatic cavity. Our cytogenetic findings suggest that partial trisomy of 1q may be a crucial secondary chromosomal abnormality in highly malignant non-Hodgkin's lymphoma. This genetic imbalance was predetermined from the primary abnormality and may be responsible for further tumor progression, as suggested from the clonal evolution in this particular case and, therefore, may be associated with the aggressive biologic behavior of malignant cells.

Clonal structural chromosome aberrations in nonneoplastic cells of the skin and upper aerodigestive tract

Cytogenetic analyses of tumors of the skin and upper aerodigestive tract have repeatedly revealed small, pseudodiploid clones characterized by balanced structural rearrangements and a high frequency of cells with nonclonal structural aberrations. However, the lack of common cytogenetic denominators within the different histologic subtypes, the discrepancy between cytogenetic findings and data obtained from flow cytometric DNA content studies, and the occasional identification of tumors with massively rearranged karyotypes indicate that the chromosome rearrangements present in pseudodiploid cells have little to do with the tumorigenesis or progression. Further support for this conclusion, and indirect evidence that the pseudolipid clones probably do not represent the tumor cell populations, derives from the present study in which clonal and nonclonal structural rearrangements were also found in short-term cultures from nonneoplastic skin and pharyngeal mucosa. It is possible that the aberrations are present in subepithelial fibroblast that have accumulated DNA damage due to extensive exposure to potentially carcinogenic agents.

Translocation (4;14) and concomitant inv(14) in a basal cell carcinoma

Chromosome analysis of short-term cultures from a basal cell carcinoma was performed. The analyzed karyotypes showed a pseudodiploid clone characterized by a der(4)t(4;14) (p14;p11) and a concomitant inversion of the same chromosome 4 involved in the t(4;14) with the breakpoints at p14 and q25.

Comparison of DNA and Karyotype Aneuploidy in Malignant Lymphomas

Tumors from 48 patients with non-Hodgkin's lymphoma were examined for flow cytometric DNA ploidy and chromosome constitution to determine the degree of concordance of these two methods. Histologically, there were 24 low-grade, 19 intermediate, and 5 high-grade lymphomas. Flow cytometry revealed an aneuploid cell population in 19% of the cases. The mean DNA index of the aneuploid tumors was 1.58 +/- 0.71. The frequency of DNA aneuploidy was only slightly higher (23%) in intermediate than in low-grade lymphomas (17%). None of the five high-grade lymphomas showed DNA aneuploidy. The chromosome study was successful in 81% of cases (39 of 48), and clonal chromosome abnormalities were observed in 92% of these (36 of 39). In most of the chromosomally abnormal clones the chromosome number was in the diploid range. Most tumors with pseudodiploid (46 chromosomes), hypodiploid (45-44 chromosomes), or hyperdiploid (47-49 chromosomes) clones were DNA diploid by flow cytometry. On the other hand, all specimens with a chromosome number exceeding 50 were DNA aneuploid by flow cytometry. Therefore, flow cytometric DNA analysis appears to be a rather coarse method that will detect aneuploidy only when there is a major increase in chromosome material.

Two unrelated clonal chromosome rearrangements in a nasal papilloma

We have cytogenetically examined short-term cultures from a nasal papilloma, a tumor type in which chromosome aberrations have hitherto not been reported. Two pseudodiploid clones were detected, giving the tumor karyotype 46,XY,t(1;3)(p31;p12)/46,XY,t(11;?)(q25;?).

Detection of the chromosomally abnormal clone in acute lymphoblastic leukemia

Bone marrow and peripheral blood from 121 children with acute lymphoblastic leukemia spent 3 hours in transit before being cultured. Cultures were harvested directly, after 24, 48, or 72 hours, and following methotrexate synchronization. Details of techniques are given. Analyzable mitoses were obtained in 78 cases. Failures contained no detectable clone and fewer than five mitoses (27 cases) or fewer than five analyzable mitoses (16 cases). A clone was found in 44 cases. In some cases the clone was found in two or more cultures, conversely a clone in the direct harvest was not always found after overnight culture and vice versa. Hyperdiploid clones were always found in the bone marrow and frequently in two or more cultures. Pseudodiploid clones found in the blood in four cases evaded detection in the bone marrow. The use of methotrexate did not yield prometaphase chromosomes or improve the yield of analyzable cells. The number of cultures employed influenced the yield of metaphases and appeared to influence clone detection. More cultures were needed to detect a pseudodiploid clone than to detect a hyperdiploid clone. Detection of a clone may be maximized by using the following combination of cultures: bone marrow direct and overnight, and peripheral blood overnight.

Chromosomes and causation of human cancer and leukemia. LIV. Near-tetraploidy in acute leukemia

Near-tetraploid cell populations were observed in a case of T-cell acute lymphoblastic leukemia (T-ALL) and in one of acute myeloblastic leukemia (AML). In the ALL case, hyperdiploid chromosomal changes, characterized by an isochromosome 17q [i(17q)], as well as other changes, were seen at the onset of the disease. At the first relapse, hypertetraploid cells appeared in about 10% of the mitoses in the bone marrow (BM), and by the second and third relapses, the hypertetraploidy was present in more than 90% of the mitoses in the BM. Even though karyotypic instability was evident, all abnormal karyotypes contained one or two i(17q) at every sampling. In spite of karyotypic instability at each relapse, karyotypic evolution was observed whenever relapse occurred. A normal female karyotype was confirmed in the BM of each period. Immunologic examinations performed at each sampling revealed no recognizable changes before and after the appearance of tetraploidy. In the AML case, which was classified as FAB M2, cytogenetic examination was performed at diagnosis and relapse. In both, hypotetraploid cells were observed in over 60% of the BM cells; the modal chromosome number was 90. Banding analysis was successful at relapse, and a pseudodiploid clone characterized by t(8;21) and a hypotetraploid clone with two t(8;21) and a loss of two Y chromosomes were observed in the same BM sample. A normal male karyotype was also observed in BM cells. In both cases, giant and bizarre blasts were seen in the BM. A close correlation between near-tetraploid mitoses and giant and bizarre blast cells in BM smears of the same samples was observed. Previously published tetraploid acute leukemia cases analyzed with banding methods were accumulated and compared with our two cases.

Banded chromosome analysis in patients with treatment-associated acute nonlymphocytic leukemia

We have analyzed G-banded metaphase chromosomes from 20 patients with treatment-associated acute nonlymphocytic leukemia (t-ANLL). Nine patients were previously treated for hematologic malignancies and 11 for solid tumors. The interval from initial therapy to t-ANLL ranged from 35 to 182 mo (median 75.5 mo). Median age at diagnosis of t-ANLL was 58.5 years. Clonal chromosome abnormalities were found in 19 patients (95%). Loss or partial deletion of the long arm of chromosomes #5 and/or #7 were most common, occurring in nine patients. These abnormalities were associated with hypodiploid complex karyotypes. Other nonrandom abnormalities recurring among karyotypes with abnormalities of chromosome #5 included loss of one #18, partial deletion of the long arm of chromosome #2, ring chromosomes, and a Philadelphia (Ph 1) chromosome. We also identified a group of five patients whose only karyotypic abnormality was addition of whole chromosomes. The remaining five patients had other karyotypic abnormalities, the most common of which were structural rearrangements in a pseudodiploid clone. Combined data from our study and the three previously published large series of patients with t-ANLL studied with banding suggest a relationship between karyotype and intensity of prior therapy, with abnormalities of chromosomes #5 and #7 occurring more often in the intensively treated patients.

Isolation and characterization of diploid clones from adult and newborn rat liver cell lines.

A high frequency of diploid and near-diploid clones were developed from cell lines derived from adult and newborn rat liver using micropipettes. There were some differences in morphology, biochemical properties and growth rate between clones. Cloned cells had low levels of tyrosine transaminase activity, glucose-6-phosphatase activity and albumin content. A diploid clone and pseudodiploid clone derived from adult rat liver cell line were positive for alpha-fetoprotein.