Telomere length shortening in patients with dementia with Lewy bodies.

BACKGROUND AND PURPOSE: Shortened telomere length has been considered to be associated with various age-related diseases, especially in dementia such as Alzheimer's disease and vascular dementia. However, changes in telomere length in dementia with Lewy bodies (DLB) remain unclear. To elucidate these changes, we set out to determine telomere length in peripheral leukocytes as well as the level of urinary 8-hydroxy-deoxyguanosine (8-OHdG) as a marker of oxidative stress in DLB. METHODS: Blood samples were obtained from 33 patients with a clinical diagnosis of probable DLB and 35 age-matched, non-demented elderly controls (NEC). Telomere length was assessed by quantitative real-time polymerase chain reaction of genomic DNA extracted from leukocytes, whereas oxidative stress was assessed on the basis of urine 8-OHdG level, which was measured using high-performance liquid chromatography. RESULTS: Telomere length was significantly shorter in the DLB group than in the NEC group. Urinary 8-OHdG levels were significantly higher in the DLB group than in the NEC group. There was a negative correlation between telomere length and age in the DLB group; however, there were no significant relationships between telomere length and clinical findings including disease duration, severity of cognitive decline, presence or absence of fluctuation in cognitive function, visual hallucinations, and Parkinsonism. In both groups, the correlation between telomere length and urinary 8-OHdG levels was not significant. CONCLUSIONS: These findings indicate that the etiopathology of DLB is considered to be an accelerated aging process.

Identification and functional signature of genes regulated by structurally different ABL kinase inhibitors.

Dasatinib is an ATP-competitive, multi-targeted SRC and ABL kinase inhibitor that can bind BCR-ABL in both the active and inactive conformations. From a clinical standpoint, dasatinib is particularly attractive because it has been shown to induce hematologic and cytogenetic responses in imatinib-resistant chronic myeloid leukemia patients. The fact because the combination of imatinib and dasatinib shows the additive/synergistic growth inhibition on wild-type p210 BCR-ABL-expressing cells, we reasoned that these ABL kinase inhibitors might induce the different molecular pathways. To address this question, we used DNA microarrays to identify genes whose transcription was altered by imatinib and dasatinib. K562 cells were cultured with imatinib or dasatinib for 16 h, and gene expression data were obtained from three independent microarray hybridizations. Almost all of the imatinib- and dasatinib-responsive genes appeared to be similarly increased or decreased in K562 cells; however, small subsets of genes were identified as selectively altered expression by either imatinib or dasatinib. The distinct genes that are selectively modulated by dasatinib are cyclin-dependent kinase 2 (CDK2) and CDK8, which had a maximal reduction of <5-fold in microarray screen. To assess the functional importance of dasatinib regulated genes, we used RNA interference to determine whether reduction of CDK2 and CDK8 affected the growth inhibition. K562 and TF-1BCR-ABL cells, pretreated with CDK2 or CDK8 small interfering RNA, showed additive growth inhibition with imatinib, but not with dasatinib. These findings demonstrate that the additive/synergistic growth inhibition by imatinib and dasatinib may be mediated in part by CDK2 and CDK8.

Telomerase inhibition with a novel G-quadruplex-interactive agent, telomestatin: in vitro and in vivo studies in acute leukemia.

The telomerase complex is responsible for telomere maintenance and represents a promising neoplasia therapeutic target. Recently, we have demonstrated that treatment with a G-quadruplex-interactive agent, telomestatin reproducibly inhibited telomerase activity in the BCR-ABL-positive leukemic cell lines. In the present study, we investigated the mechanisms of apoptosis induced by telomerase inhibition in acute leukemia. We have found the activation of caspase-3 and poly-(ADP-ribose) polymerase in telomestatin-treated U937 cells (PD20) and dominant-negative DN-hTERT-expressing U937 cells (PD25). Activation of p38 mitogen-activated protein (MAP) kinase and MKK3/6 was also found in telomestatin-treated U937 cells (PD20) and dominant-negative DN-hTERT-expressing U937 cells (PD25); however, activation of JNK and ASK1 was not detected in these cells. To examine the effect of p38 MAP kinase inhibition on growth properties and apoptosis in telomerase-inhibited cells, we cultured DN-hTERT-expressing U937 cells with or without SB203580. Dominant-negative-hTERT-expressing U937 cells stopped proliferation on PD25; however, a significant increase in growth rate was observed in the presence of SB203580. Treatment of SB203580 also reduced the induction of apoptosis in DN-hTERT-expressing U937 cells (PD25). These results suggest that p38 MAP kinase has a critical role for the induction of apoptosis in telomerase-inhibited leukemia cells. Further, we evaluated the effect of telomestatin on the growth of U937 cells in xenograft mouse model. Systemic intraperitoneal administration of telomestatin in U937 xenografts decreased tumor telomerase levels and reduced tumor volumes. Tumor tissue from telomestatin-treated animals exhibited marked apoptosis. None of the mice treated with telomestatin displayed any signs of toxicity. Taken together, these results lay the foundations for a program of drug development to achieve the dual aims of efficacy and selectivity in vivo.

Telomerase activity in lung cancer cells obtained from bronchial washings.

BACKGROUND: Telomerase, a ribonucleoprotein enzyme that functions in the maintenance of telomeres (specialized structures at the ends of chromosomes), has been reported to be a novel diagnostic marker for malignant diseases. We sought to determine whether measurement of telomerase activity in bronchial washings is of value in the diagnosis of lung cancer. METHODS: Extracts of cells in bronchial washings were analyzed for telomerase activity by use of a telomeric repeat amplification protocol (TRAP) assay. Telomerase activity inside cells was evaluated by use of an in situ TRAP assay. The results of both TRAP assays were compared with those obtained from cytologic examination, which employed standard Papanicolaou staining. RESULTS: When results from the two TRAP assays were combined, telomerase activity was detected in bronchial washings from 18 (82%; 95% confidence interval [CI] = 60%-95%) of 22 patients with lung cancer. In contrast, cancer cells were detected by cytologic examination in the bronchial washings of nine (41%; 95% CI = 21%-64%) of the same 22 patients, a statistically significant difference (two-sided P = .0061). In patients with lung cancer, telomerase-positive cells could be detected in bronchial washings irrespective of tumor location--11 of 14 (79%; 95% CI = 49%-95%) peripheral cancerous lesions and seven of eight (88%; 95% CI = 47%-100%) central cancerous lesions were detected by use of TRAP assays (for comparison, two-sided P = .5349). CONCLUSIONS: A high percentage of patients with lung cancers had detectable telomerase activity in bronchial washings. Thus, the use of a cell extract-based or an in situ TRAP assay in addition to cytologic examination may make the diagnosis of lung cancer more reliable.

Cytogenetic characterization of putative human myeloblastic leukemia cell lines (ML-1, -2, and -3): origin of the cells.

Cytogenetic studies were performed on ML cell lines (ML-1, -2, and -3), as well as on the leukemic cells of a patient from whom the ML cells were derived. The ML-1 cell line showed numerical and structural cytogenetic changes, i.e., -Y, 1p-, 6q-, 11q-, +12, +13q+, 14q-, and 17q-. The ML-2 cell line had two copies of the 13q+, whereas the ML-3 cells contained three clones, i.e., 47,X,-Y,1p-,6q-,11q-,+12,+13q+, 48,X,-Y,1p-,6q-,+6q-,11q-,+12,+13q+, and 49,X,-Y,1p-,6q-,+6q-, 11q-,+12,+13q+,+13q+. The neoplastic cells, when the patient was diagnosed as having T-cell malignant lymphoma (Stage IV), had the 11q- and 13q+. The leukemic cells in a subsequent acute myeloid leukemia phase of this patient contained structural (1p- and 6q-) and numerical (+12, -Y and +2D-group chromosomes: two 13q+) changes in addition to the 11q-. These findings suggest that the acute myeloid leukemic cells of this patient probably originated from the neoplastic cells of the preceding T-cell lymphoma, and that the chromosome changes originally seen in the lymphoma cells were preserved in the established ML cell lines, though the cells of these lines had myeloid characteristics.

Methylation status of T-cell receptor beta-chain gene in B precursor acute lymphoblastic leukemia: correlation with hypomethylation and gene rearrangement.

Epigenetic changes may play a role in genetic alterations in cancer cells, but little is known about this phenomenon. In this study we examined the correlation between rearrangement and methylation status of the T-cell receptor (TCR) beta-chain gene in 23 patients with B precursor acute lymphoblastic leukemia (ALL). In B precursor ALL, all patients had a CCmeGG sequence in the C beta 2 region, a pattern similar to that observed in normal mature B-cells. Approximately 55% of patients with B precursor ALL exhibiting a hypomethylated CCGG sequence at the J beta 1 region showed rearrangement of this region. Furthermore, the same allele of rearranged J beta 1 always contained an unmethylated sequence in the region, although another allele without rearrangement contained methylated J beta 1. By contrast, none of the patients had a rearrangement in the J beta 1 region without hypomethylation. Therefore, rearrangement of the J beta 1 region may link to the hypomethylation status of this region. A close association between hypomethylation of the J beta 1 region may promote accessibility to a putative common recombinase to produce TCR J beta 1 rearrangement. In contrast, about 45% of patients with a hypomethylated J beta 1 did not show rearrangement in this region, thus allowing categorization of B precursor ALL patients into subtypes, according to the combination of TCR beta-chain gene rearrangement and hypomethylation status, especially in the J beta 1 region.

Loss of a Hu-ets-1 allele in human leukemia cell lines ML-1, -2, and -3 with a chromosome change at 11q24.

The ML cell lines (ML-1, -2, and -3) were derived from the cells of a patient with T-cell malignant lymphoma who developed acute myeloblastic leukemia and whose cells showed a primary chromosome change at band 11q24. Surface marker studies of the ML cells showed that they had both myeloid (MCS-1, MCS-2, and OKM-1) and some T-lymphocyte (3A1/Leu-9 and OKT-4/Leu-3a) characteristics. Molecular studies on these lines were performed in order to determine the possible involvement of the Hu-ets-1 gene, since it is located at band 11q23----q24. All ML cell lines showed half the intensity of the Hu-ets-1 DNA bands as compared to those of controls (karyotypically normal B-cell lines). In contrast, DNAs from leukemia cells with t(4;11)(q21;q23) or t(1;11)(q21;q23 or q24) showed no rearrangement, deletion, or amplification of the ets-1 gene. These findings indicate that a chromosome region (11q24----qter), including the Hu-ets-1 gene, of the ML cells is deleted as a result of the primary cytogenetic change and that heterogeneity is present in the mechanism of human leukemia involving the 11q23----q24 region.

Recurrent chromosome changes at 3p21 in Epstein-Barr virus-transformed cells derived from human prolymphocytic leukemia.

Cytogenetic studies of Epstein-Barr virus-transformed lymphoblastoid cells obtained from a patient with prolymphocytic leukemia revealed the cells to contain recurrent chromosome aberrations involving band 3p21. The in vivo leukemic cells from which the cell lines originated contained a der(3)t(3;17?)(p21;q11?) and a der(13)t(13;3)(q34;p21), as well as numerical (-Y, -8, and -17) and other structural [8p- and der(8)t(8;?)(q13?;?)] changes. The cells in established culture showed additional chromosome aberrations involving band 3p21 of the previously normal and abnormal chromosomes 3. After 200 days of culture, the cells contained a new translocation, i.e., t(3;14)(p21;q32). The cells showed further chromosomal breakage and reunion at band 3p21 at later passages. The affected chromosomal band (3p21) is close to one of the constitutive fragile sites, i.e., 3p14.2. Northern blot analysis of the messenger RNA of the cultured cells did not show an increased or altered expression of the c-raf-1 protooncogene (located at 3p25) when compared with the mRNA of Epstein-Barr virus-transformed lymphoblastoid cell lines from normal subjects with a normal karyotype. Also, the established cells did not show DNA rearrangements or RNA alterations of the c-myc gene.

T-cell receptor beta chain gene rearrangement in acute myeloid leukemia always occurs at the allele that contains the undermethylated J beta 1 region.

The epigenetic phenomenon could play a role in the interaction between chromatin and DNA-binding enzymes, allowing us to consider an association between the phenomenon and gene rearrangement. The correlation between methylation status and rearrangement of the T-cell receptor (TCR) beta chain gene in leukemia cells obtained from patients with acute myeloid leukemia (AML) was examined. All of the AML patients with a TCR-beta rearrangement had hypomethylated CCGG sequences within the J beta 1 region on the rearranged allele, while the germline allele had completely methylated CCmeGG sequence in this region, indicating a strong association between hypomethylation status and rearrangement of the TCR beta chain gene. In the DNA from AML patients with or without a TCR-beta rearrangement, the C beta 2 region contained completely methylated CCmeGG sequences, even though they express T-cell-associated antigens, including CD7; this pattern is quite different from that observed in T-cell neoplasias. Moreover, some AML patients showed a TCR-beta rearrangement without the presence of immunoglobulin heavy-chain gene rearrangement, suggesting that TCR beta chain gene involvement in AML is required for unknown factors other than common recombinase activity.

Telomere shortening associated with disease evolution patterns in myelodysplastic syndromes.

We identified the telomere length at different hematological phases in 16 patients with myelodysplastic syndromes (MDS), showing disease evolution with a conventional Southern blot hybridization using the (TTAGGG)4 probe. The MDS patients studied were classified into three groups according to the pattern of telomere length reduction. The first group had telomere shortening at the time of disease diagnosis. In four of the six MDS patients in this group, the disease progressed within 6 months postdiagnosis and each of them survived for less than 1 year. Moreover, in this group four patients showed a 5q anomaly with or without additional changes, and 50% of patients in this group had complex chromosome abnormalities. The patients in the second group showed reductions in telomere length after disease progression; two of these three patients showed gradual disease progression and had one or two chromosome abnormalities. The third group comprised the remaining seven MDS patients; they showed no telomere reduction by disease evolution. Two patients in this group experienced rapid disease progression. These results may indicate that telomere reduction is linked to disease evolution in some MDS patients, perhaps as a result of genomic instability because patients with complex chromosome abnormalities were clustered in the first group. However, because some MDS patients show disease progression without telomere reduction, genetic changes, including point mutations of certain gene(s), may also contribute to disease progression. We further noted that telomere shortening at the time of MDS diagnosis might indicate a poor MDS prognosis.

A Ki-1 (CD30)-positive T (E+, CD4+, Ia+)-cell line, DL-40, established from aggressive large cell lymphoma.

A new human lymphoma cell line, designated DL-40, was established from the peripheral blood of a 64-year-old woman with leukemic conversion of aggressive large cell lymphoma. The cell line grew in suspension with or without forming clumps of cells and exhibited large, round, or multiple nuclei in the relatively abundant cytoplasm that was positive for acid phosphatase. The cells expressed a Ki-1 antigen (CD30), E+, CD2+, CD4+, CD45+, Ia+ phenotype and had rearranged T-cell receptor beta chain but were negative for CD15, HTLV-I, and Epstein-Barr virus nuclear antigen. Chromosome analysis of this cell line showed a human female karyotype with complex hyperdiploid abnormalities. DL-40 cells produced tumors histologically similar to the original lymphoma when transplanted into nude mice and immunosuppressed hamsters. The DL-40 cell line could provide a useful tool for the understanding of biology of the Ki-1-positive non-Hodgkin's lymphoma.

Cytological detection of telomerase activity using an in situ telomeric repeat amplification protocol assay.

A previously reported highly sensitive assay for measuring telomerase activity on cell and tissue extracts indicates that most human tumor tissues, but not cells adjacent to tumors, have detectable telomerase activity. Although this assay has provided a significant amount of information about the presence or absence of telomerase activity, it does not indicate whether all cells within a tumor have telomerase activity or whether only a subset does. The present report demonstrates the ability to advance this technology to an in situ assay. Using fluorescent telomerase primers and in situ PCR, we show that telomerase activity can be detected at the cellular level. This study demonstrates that telomerase activity is not detected in normal cells but is detected in tumor cells of clinical specimens and in tumor-derived cell lines.

Chromosome change at 16q22 in nonlymphocytic leukemia: clinical implication on leukemia patients with inv(16) versus del(16).

Nineteen patients with inv(16)(p13q22) or del(16) in myeloid leukemia are described. Eight showed inv(16)(p13q22), including one with de novo acute myeloid leukemia (AML-M2) and seven with de novo acute myelomonocytic leukemia (AMML-M4). Additional chromosome changes were detected in five of the cases; the most common change was trisomy 22. All but one of the de novo M2 and M4 leukemia patients with inv(16)(p13q22) showed initial bone marrow eosinophilia (greater than 5%) with basophilic granules. The remaining 11 showed deletion of the long arm of a chromosome no. 16 [del(16)(q22 or q23)]. Eight of the 11 were diagnosed as having chronic myelomonocytic leukemia, three transformed into an acute phase with M4 morphology; none of them gained complete remission. Two of the remaining three patients with del(16) were diagnosed as having M4 leukemia without marrow eosinophilia. The remaining one was a case of M4 leukemia following a myelodysplastic syndrome. The findings indicate that del(16) might be related to chronic myelomonocytic leukemia or leukemia with a prior history of myelodysplastic syndrome without evidence of marrow eosinophilia. On the other hand, inv(16)(p13q22) is highly associated with de novo AML especially AMML-M4 with bone marrow eosinophilia and a favorable prognosis.

Elevated plasma level of differentiation inhibitory factor nm23-H1 protein correlates with risk factors for myelodysplastic syndrome.

We measured plasma nm23-H1 level (nm23-H1), a differentiation inhibitory factor, by an enzyme-linked immunosorbent assay (ELISA) in patients with aplastic anemia (AA) and myelodysplastic syndrome (MDS). The nm23-H1 in AA was not significantly elevated when compared to normal subjects (6.66 +/- 1.20 ng/ml vs 5.13 +/- 0.81 ng/ml; P = 0.274). In contrast, MDS patients had significantly high levels of nm23-H1 compared not only to normal subjects (11.16 +/- 1.42 vs 5.13 +/- 0.81 ng/ml; P = 0.0004) but also to those of the AA group (11.16 +/- 1.42 ng/ml vs 6.66 +/- 1.20 ng/ml; P = 0.018). In the MDS group of patients, no significant difference was observed in the nm23-H1 levels between patients with refractory anemia (RA) and RA with excess blasts (RAEB)/RAEB in transformation (10.71 +/- 1.61 ng/ml vs 9.24 +/- 2.66 ng/ml; P = 0.672). Of the patients with RA, patients with low risk according to the International Prognostic Scoring System (IPSS) had significantly low levels of nm23-H1 compared to those of IPSS INT-1 level cases (6.40 +/- 1.36 ng/ml vs 13.05 +/- 2.50 ng/ml; P = 0.0028), suggesting that nm23-H1 may be useful as a prognostic marker for MDS, especially in low risk patients.

The methylation status of the major breakpoint cluster region in human leukemia cells, including Philadelphia chromosome-positive cells, is linked to the lineage of hematopoietic cells.

The Philadelphia (Ph) translocation [t(9;22)(q34;q11)] is the most common genetic abnormality in human leukemia; a transposition of the ABL gene to the major-breakpoint cluster region (M-BCR) is associated with the pathogenesis in Ph+ chronic myelogenous leukemia (Ph+ CML) and in some cases of Ph+ acute leukemia (Ph+ AL). Our current understanding of the methylation of human genomes allows us to consider the association between the epigenetic phenomenon and the control of differentiation and proliferation in mammalian cells. In order to determine whether the methylation status of the M-BCR is associated with breakpoint-localization in this region and with the lineage of hematopoietic cells, we have examined 28 patients with Ph+ leukemias, including nine with Ph+ AL, six patients with acute myeloblastic leukemia without Ph (Ph- AML), and five patients with Ph- acute lymphoblastic leukemia (Ph- ALL); using the restriction endonuclease isochizomers, MspI and HpaII. In CML patients in the chronic phase, the hypomethylated status within the normal M-BCR allele is heterogeneous. In contrast, patients with Ph+ CML in the lymphoid blast crisis phase exhibited a 2.5/2.7 kb band with a complete disappearance of the germline M-BCR fragment (type L). This pattern is consistently noted in Ph- ALL cells, and the pattern is quite different from that found in myeloid blast crisis or Ph- AML (type M). In patients with M-BCR-nonrearranged Ph+ ALL, it is suggested that the M-BCR methylation patterns are cell-lineage specific but some Ph+ ALL cells had a hypomethylation pattern that was identical to that observed in Ph- AML, suggesting a distinction of genetic diversity of leukemia cells with the Ph chromosome, especially Ph+ AL.

GATA-1, GATA-2, and stem cell leukemia gene expression in acute myeloid leukemia.

Transcription factors play an important role in the normal developmental process of hematopoietic cells. However, expression of transcription factors and its implication in various human leukemias is not well understood. We have studied GATA-1, GATA-2, and stem cell leukemia (SCL) gene expression in 30 patients with acute myeloid leukemia (AML) by the reverse transcription-polymerase chain reaction assay. In AML both GATA-1 and SCL genes were commonly expressed in M6 and M7 leukemias, and also in leukemias bearing the platelet-associated antigen. We found some AML patients with GATA-1, but not SCL expression. Most CD7+ AML and t(8;21)(q22;q22)-AML were included in this group, which often demonstrated immunoglobulin heavy chain and/or T-cell receptor gene rearrangements. Consequently, GATA-1+ SCL- AML may originate from early myeloid progenitors. Moreover, most AML patients of the M3, M4, or M5 groups were GATA-1- SCL-. Our data suggest that the expression pattern of transcription factors may help to define distinct phenotypes of AML cells.

Immunoglobulin and T cell receptor gene rearrangements in Philadelphia chromosome-positive leukemia: a different involvement pattern in blast crisis and acute leukemia.

We have analyzed the configuration of the immunoglobulin heavy (IgH) chain gene and the T cell receptor (TCR) chain (beta, gamma, and delta) genes in a group of 22 leukemia patients with the Philadelphia (Ph) chromosome. The group consisted of 14 patients with chronic myelogenous leukemia in blast crisis (CML-BC) and eight with Ph-positive acute leukemia (Ph + AL); these diagnoses were based on hematologic and cytogenetic features. In CML-BC patients, an IgH joining region rearrangement was detected only in patients with CD10 expression; TCR-beta, -gamma, or -delta rearrangements were associated with IgH involvement. In contrast, five of the eight Ph+ AL patients had breaks within the major breakpoint cluster region (M-BCR), and four of them had IgH involvement. Of the remaining three Ph+ M-BCR nonrearranged AL patients, only one showed IgH rearrangement. In addition, TCR-beta involvement was sometimes detected in Ph+ AL patients (two of the eight patients) with or without rearranged M-BCR, and no PH+ AL case displayed rearranged TCR-gamma. These findings suggest that genotypic changes in CML-BC are usually associated with phenotypic results of the neoplastic cells: the expression of CD10 in CML-BC patients is accompanied by the involvement of IgH with frequent TCR rearrangements which possibly are due to the common recombinase activity. On the other hand, the mechanism of the involvement of IgH in Ph+ AL patients without rearranged M-BCR seems different from that observed in Ph+ leukemia patients with rearranged M-BCR, although TCR involvement could occur whether or not the leukemia cells had a rearranged M-BCR in Ph+ AL patients.

Telomerase activity and cytogenetic changes in chronic myeloid leukemia with disease progression.

Progressive telomere shortening is thought to be important in the regulation of cellular senescence and that the upregulation or reactivation of telomerase activity may be a critical if not rate limiting step in the development of neoplastic cells. To obtain information about telomeres and telomerase activity in hematopoietic neoplasia at various disease stages, we evaluated 54 samples obtained from 41 patients with chronic myeloid leukemia (CML) using a combination of fluorescent-telomeric repeat amplification protocol and an internal telomerase assay standard. The terminal restriction fragment (TRF) lengths in the blast phase was reduced compared to that in the chronic phase (4.53 +/- 0.72 kb vs 6.13 +/- 1.68 kb; P = 0.0005). All samples obtained from CML in the chronic phase (n = 33) had detectable telomerase activity above background, regardless of age. In the blast phase (n = 21), a significant increase of telomerase activity was detected compared to that in the chronic phase (33.84 +/- 37.86% vs 6.08 +/- 3.21; P = 0.016). Among patients in the blastic phase, 50% of patients had moderate to high telomerase activity (>10 relative value), and the remaining patients had telomerase activity higher than that in the normal peripheral blood cells. No significant differences in hematologic findings, duration of chronic phase or blast phase, and telomere length in the blastic phase were noted between these two groups separated by telomerase activity. CML patients with moderate to high telomerase activity had a high frequency of additional cytogenetic changes (P = 0.01).

Treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia: a pilot study which raises important questions.

Acute lymphoblastic leukemia (ALL) patients with a Philadelphia chromosome (Ph+ ALL) were treated with a combination of antineoplastic drugs recommended for both myeloid and lymphoid leukemia (BHAC-DMPV: behenoylcytosine arabinoside, daunorubicin, 6-mercaptopurine, prednisolone, and vincristine). Ph+ ALL patients with chromosome breaks which occur within the major breakpoint cluster region (M-BCR rearranged Ph+ ALL) were treated with natural interferon-alpha (IFN-alpha) after entering complete remission. In this study, four of seven patients with Ph+ ALL had M-BCR rearrangement, and all achieved complete remission with karyotypic normalization. Subsequent cytogenetic analysis during complete remission in two ALL patients with M-BCR rearrangement revealed that the percentage of bone marrow cells with the Ph chromosome increased, while the bone marrow maintained remission status. This cytogenetic-hematological discrepancy led us to consider that M-BCR rearranged Ph+ ALL might be a variant of chronic myelogenous leukemia, therefore, three Ph+ ALL patients with M-BCR rearrangement were treated with IFN-alpha after achieving complete remission. In contrast, only one of three patients with M-BCR non-rearranged Ph+ ALL obtained complete remission.

Comparison between immunogenotypic findings in de novo AML and AML post MDS.

We compared immunogenotypic findings in 73 patients with de novo acute myeloid leukemia (AML) and 30 patients with AML developed in myelodysplastic syndrome (AML post MDS) to determine the biological difference between these hematopoietic neoplasias. Lymphoid-associated antigens were detected in 13 patients with de novo AML, four of whom exhibited rearrangement of the immunoglobulin heavy-chain (IgH) gene. T-cell receptor (TCR) gene rearrangements were detected in 10 patients with de novo AML who did not have lymphoid-associated antigens, none of whom carried rearranged IgH. This group included two AML patients with trilineage dysplasia. Neither lymphoid markers nor IgH rearrangement was detected in any of the 30 patients with AML post-MDS; TCR rearrangements were detected in eight out of 30 patients, TCR-beta rearrangements in six out of 30, and TCR-delta rearrangements in five out of 30. The TCR rearrangement without rearranged IgH in some AML post MDS patients might not be due to a common recombinase activity, and this alteration may link to genomic instability. Some patients with de novo AML also showed this pattern, suggesting a close biologic association between AML post MDS and some patients with de novo AML.