Expression of signal transducers and activators of transcription proteins in acute myeloid leukemia blasts.

Hematopoietic cytokine receptor signaling pathways involve activation of signal transducers and activators of transcription (STAT) proteins, which are postulated to be involved in cellular differentiation. Aberrant STAT isoforms (beta forms rather than the normal alpha forms) have been described and have been found to block the normal signaling pathway from the receptor. Bcr/Abl proteins have been suggested to directly activate STATs, without exposure to growth factors. We asked whether STATs play a role in leukemogenesis. We analyzed constitutive and induced patterns of STAT activity in pretreatment blasts from 36 newly diagnosed acute myeloid leukemia (AML) patients and studied protein tyrosine kinases (PTKs) that may be involved in STAT activity, using in vitro and in-gel kinase assays. The beta forms were expressed in 21 of 27 samples (78%). Constitutive STAT3 and STAT5 activity was found in samples from 28 and 22% of patients, respectively. Response to exogenous cytokines identified two groups. STAT activity in one group was modulated by exogenous cytokines: constitutive STAT activity increased in some patients but decreased or disappeared in response to cytokines in others. The second group was cytokine insensitive. Additionally, we found constitutive PTK activity in two patients whose blasts demonstrated constitutive STAT activity, suggesting that PTKs use cytokine receptor signal pathways to activate STATs in AML blasts without exposure to exogenous cytokines. Our data suggest that (a) constitutive expression of aberrant STATs may be involved in blocking differentiation of AML blasts, (b) exogenous cytokines may activate STAT-inhibitory pathways, and (c) STATs may be activated by PTKs in some AML blasts.

Partial tandem duplication of ALL1 as a recurrent molecular defect in acute myeloid leukemia with trisomy 11.

Gains of a single chromosome are frequent cytogenic findings in human cancer, but no molecular rearrangement has been consistently associated with any trisomy. In acute myeloid leukemia (AML), trisomy 11 (+11) occurring as a sole abnormality is the third most common trisomy. We have shown that the ALL1 gene, located at 11q23, can be rearranged as a result of a partial tandem duplication in two such cases of AML. To test the hypothesis that the partial tandem duplication of ALL1 is the recurrent molecular defect in cases of AML presenting with +11 as a sole cytogenic abnormality, we performed Southern analysis and PCR for defects of ALL1 in 17 cases of AML and one case of myelodysplastic syndrome with +11 or +11q but without cytogenic evidence of a structural abnormality involving 11q23. Twelve cases (67%) had rearrangement of ALL1, including 10 of 11 patients (91%) with +11 as a sole abnormality and 2 of 7 cases (29%) with +11 and other aberrations; all were classified as FAB M1 or M2. In 10 of the 12 cases, material was available for additional characterization; a partial tandem duplication of ALL1 was detected in each of these 10 cases (100%). Four cases demonstrated previously unreported duplications, two of which were detectable only by reverse transcription-PCR. Four patients with the ALL1 duplication also displayed a loss of material from 7q, suggesting an association between these two findings. We conclude that the partial tandem duplication of ALL1 is present in most, if not all, cases of AML with +11 as a sole abnormality, and can be found in cases of AML with +11 or +11q accompanied by other cytogenic abnormalities. The duplication is more prevalent in AML than was recognized previously in part because its size and location vary considerably, requiring a variety of molecular probes for detection. Our finding of the ALL1 duplication as a consistent defect in patients with +11 represents the first identification of a specific gene rearrangement associated with recurrent trisomy in human cancer.

Rearrangement of ALL1 (MLL) in acute myeloid leukemia with normal cytogenetics.

Approximately 45% of adults with acute myeloid leukemia (AML) have normal cytogenetics and therefore lack structural abnormalities that can assist in the localization and characterization of molecular defects. The partial tandem duplication of the ALL1 (MLL) gene has been found in several such cases of AML, yet its frequency and clinical significance are unclear. We performed Southern analysis of the ALL1 gene in pretreatment samples from 98 AML patients with normal cytogenetics. Eleven of 98 such patients (11%; 95% confidence interval, 6-19%) showed rearrangement of ALL1 at diagnosis. The partial tandem duplication of ALL1 was responsible for ALL1 rearrangement in all such cases examined, making it a frequent molecular defect in adult AML patients with normal cytogenetics. Furthermore, patients with ALL1 rearrangement had a significantly shorter duration of complete remission when compared to patients without ALL1 rearrangement (P = 0.01; median, 7.1 versus 23.2 months). This defect defines for the first time a subset of AML patients with normal cytogenetics who have short durations of complete remission and thus require new therapeutic approaches.

Expression of c-mpl mRNA, the receptor for thrombopoietin, in acute myeloid leukemia blasts identifies a group of patients with poor response to intensive chemotherapy.

PURPOSE: c-mpl, the human homolog of v-mpl, is the receptor for thrombopoietin. Given that c-mpl expression carries an adverse prognosis in myelodysplastic syndrome and given the prognostic significance of expression of other growth factor receptors in other diseases, we attempted to determine whether c-mp/mRNA expression is a prognostic factor in acute myeloid leukemia (AML). PATIENTS AND METHODS: We analyzed bone marrow samples from 45 newly diagnosed AML patients by reverse-transcription polymerase chain reaction. RESULTS: Samples from 27 patients (60%) expressed c-mpl mRNA (c-mpl+); their clinical and laboratory features were compared with those of the 18 patients without detectable levels of c-mpl(c-mpl-). No significant differences in age, sex, leukocyte count, French-American-British subtype, or karyotype group were found. c-mpl+ patients more commonly had secondary AML (41% v 11%; P = .046) and more commonly expressed CD34 (67% v 12%; P = .0004). There was no significant difference in complete remission (CR) rate. However, c-mpl+ patients had shorter CR durations (P = .008; median, 6.0 v > 17.0 months). This was true when only de novo AML patients were considered and when controlling for age, cytogenetics, or CD34 expression. There was a trend toward shorter survival in c-mpl+ patients (P = .058; median, 7.8 v 9.0 months). CONCLUSION: These data suggest that c-mpl expression is an adverse prognostic factor for treatment outcome in adult AML that must be considered in the analysis of clinical studies using thrombopoietin in AML.

Simultaneous presentation of acute monoblastic leukemia and mantle cell lymphoma: case report and review of the literature.

This paper reports a 73-year old woman with simultaneous presentation of acute monoblastic leukemia (acute myeloid leukemia (AML), French-American-British (FAB) type M5a) and mantle cell lymphoma. The patient presented with wasting, generalized lymphadenopathy, an extensive infiltrative rash and pancytopenia. Bone marrow and lymph node histopatholology showed extensive infiltration by leukemic monoblasts. Marrow cytogenetics revealed a complex karyotype, including t(8;16)(p11;p13). Flow cytometric immunophenotyping of peripheral blood, lymph node and bone marrow demonstrated two populations, expressing CD5, CD19, CD20 and CD22 and CD45, HLA-DR, CD13, CD33, CD14 and CD38, respectively. A focus of abnormal lymphocytes in the lymph node biopsy demonstrated BCL1 expression and t(11;14)(p11;p13) by fluorescence in situ hybridization and immunoglobulin heavy chain gene rearrangement by the polymerase chain reaction. The patient received infusional cytarabine, daunorubicin and etoposide chemotherapy, with complete remission of both the AML and the mantle cell leukemia. To the authors' knowledge, this is the first report of simultaneous presentations of AML, FAB M5a and mantle cell lymphoma. The case is discussed and the literature is reviewed.

Cell cycle analysis of stimulated lymphocytes of B-cell chronic lymphocytic leukemia.

To clarify the cell cycle duration of stimulated cells in B cell chronic lymphocytic leukemia (B-CLL), sister chromatid differentiation (SCD) methodology was utilized. So-called polyclonal B-cell activators (PBA), i.e., staphylococcus bacteria strain Cowan I (Cowan I), pokeweed mitogen (PWM), Epstein-Barr virus (EBV), and lipopolysaccharide W from E. coli 055:B5 (LPS), were examined. Most metaphases on day 2 (48 hr) of culture were in first division (M1), and about half of the metaphases on day 3 (72 hr) of culture were in the second division (M2), and many of the metaphases on day 4 (96 hr) of culture were in the third division. These facts suggest that the optimal culture time for cytogenetic study of B-CLL should be 3 days or less to avoid in vitro artifacts.

Cytogenetic studies of stimulated lymphocytes in hairy cell leukemia.

Using a sister chromatid differentiation (SCD) technique, cell cycle analysis in lymphocytes from two patients with hairy cell leukemia (HCL) revealed it to be similar to cell cycle progression of normal lymphocytes stimulated with lipopolysaccharide W from Escherichia coli 0.55:B5 (LPS). It appears that LPS can readily stimulate the leukemic cells of HCL into mitosis. In the two cases of B cell HCL studied, one (case 1) was revealed to have an abnormal clone with a missing chromosome #22 that was related to the production of lambda-chains.

Karyotypic findings in a case of prolymphocytic leukemia with a history of radiation exposure.

Cytogenetic examination, utilizing B- and T-cell mitogens, of the peripheral blood lymphocytes of a patient with the prolymphocytic variant of chronic lymphocytic leukemia (CLL) and a history of radiation exposure revealed two abnormal clones. One clone with 48 chromosomes (+t(6;12),6q-, +12,14q+) may be derived from CLL cells, whereas the clone with 46 chromosomes and a ring #11 possibly originated from normal T and/or B cells affected by past irradiation.

Chromosome changes in mycosis fungoides in an XYY male.

A 32-year-old white male was diagnosed as having mycosis fungoides in 1976; bone marrow biopsy and aspiration in August 1984 revealed infiltration with neoplastic cells. Cytogenetic analysis of the cells from the bone marrow specimen showed that 48 of 50 metaphases contained an extra Y chromosome (i.e., 47,XYY). The remaining two cells were hypotetraploid and hyperpentaploid, respectively, with a common marker derived from chromosome #2. The metaphases obtained by PHA stimulation of peripheral blood cells showed a 47,XYY pattern. An interleukin 2 (IL-2) dependent T-cell line was established from the patient's blood mononuclear cells; all metaphases of this line had an extra Y chromosome. Thus, this case is one of a mycosis fungoides developing in an XYY male.

Extra Y chromosome in chronic lymphoproliferative disorders.

Using separated lymphocytes from 95 male patients with B-cell lymphoproliferative disorders, we have established both Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines and short-term cultures with polyclonal B-cell mitogens. Cytogenetic studies of these patients revealed an extra Y chromosome in 4 of 71 male cell lines examined. An extra Y chromosome appeared to be the sole karyotype change (47,XY, + Y) in 2 of these 4 patients. The extra Y chromosome was accompanied by extra copies of chromosomes 12 and 21 (48,XY, + Y, + 12 and 48,XY, + Y, + 21) in the other 2 patients, respectively. The possible oncological role of the extra Y chromosome in the initiation of leukemia is discussed.

Deletion of chromosome 22 without bcr rearrangement and without juxtaposition of c-abl in a case of acute myeloid leukemia.

We describe a patient with acute myeloid leukemia (AML) who had a deletion of chromosome 22 at q11 as a sole chromosomal abnormality, resulting in the karyotype 46,XY,del(22)(q11). Southern blot analysis showed no bcr rearrangement and fluorescence in situ hybridization indicated no juxtaposition of c-abl. This study indicates that molecular events other than bcr rearrangement and c-abl juxtaposition were involved in leukemogenesis in this patient. We hypothesize that a tumor suppressor candidate gene may be located on the long arm of chromosome 22; its loss may lead to malignant transformation.

Cytogenetic evidence for clonal evolution in B-cell chronic lymphocytic leukemia.

Sequential cytogenetic studies were performed in eight of ten patients with B-cell chronic lymphocytic leukemia presenting with trisomy 12 as the sole chromosomal abnormality. Follow-up studies of peripheral blood lymphocytes revealed that the karyotypes retained the sole abnormality of trisomy 12 in five cases, trisomy 12 converted to a normal karyotype during remission in one case, additional chromosome changes (-X,14q-) along with trisomy 12 appeared in one patient and multiple chromosome changes with or without trisomy 12 appeared in the remaining patient. The findings indicate that other chromosome changes in addition to trisomy 12 may develop as a result of clonal evolution or dedifferentiation, though the possibility that in two patients these changes may be related to chemotherapy and/or irradiation could not be ruled out entirely.

A new approach in the diagnosis and follow-up of bladder cancer. FISH analysis of urine, bladder washings, and tumors.

The aim of the present study was to ascertain whether fluorescence in situ hybridization (FISH) of urine could be a useful approach in bladder cancer. Herein, we present the cytogenetic and FISH findings in patients with and without bladder cancer. The samples examined with FISH consisted of urine, bladder washings, and tumor tissue, when available. The results obtained show that the FISH technique, particularly when used on urine, is a very useful tool in the diagnosis, early detection, and management of bladder cancer.

Translocation t(6;9)(p22.3;q34) in myelodysplastic syndrome--refractory anemia with excess blasts.

A 69-year-old male patient with refractory anemia with excess blasts (RAEB) was found to have a consistent chromosomal abnormality, t(6;9)(p22.3;q34), in the bone marrow and unstimulated peripheral blood cells. Twenty patients with t(6;9) and leukemia have been reported; some of them had a myelodysplastic syndrome (MDS) before developing overt ANLL. Our patient was still in the MDS stage when the t(6;9) was found. This result suggests that t(6;9) represents one of the pathways from MDS to leukemia in patients with ANLL.

Induction of superoxide dismutase, chromosomal aberrations and sister-chromatid exchanges by paraquat in Chinese hamster fibroblasts.

We have recently shown that Bloom syndrome fibroblasts have elevated levels of superoxide dismutase activity compared to those of normal fibroblasts. Based on this observation we decided to test whether an increased rate of superoxide radical production could be responsible for the induction of superoxide dismutase and of chromosomal aberrations and sister-chromatid exchanges characteristic of Bloom syndrome. Utilizing the superoxide-generating herbicide paraquat in Chinese hamster fibroblasts, we assayed the cells for dismutase activity, chromosomal aberrations and sister-chromatid exchanges. All 3 parameters investigated demonstrated a dose-dependent increase with paraquat and, consequently, with the superoxide produced. Since the induction of the enzyme is mediated by its substrate, the superoxide anion radical, we concluded that the increased dismutase activity (in Bloom syndrome and paraquat-treated cells) may be a secondary manifestation of an overall imbalance in oxygen metabolism and that this elevated enzymatic activity is insufficient to detoxify the high superoxide levels, which results in elevated levels of chromosomal damage.

Concurrent presence of inv(14)(q11q32) and t(4;11)(q21;q23) in pre-B acute lymphoblastic leukemia.

The inv(14)(q11q32) is a non-random chromosomal aberration which has been associated with a variety of T-cell malignancies. We have studied a case of inv(14)(q11q32) that is unique in several respects. First, the inversion, which is expressed at the mRNA level, occurred in the context of a pre-B acute lymphoblastic leukemia (ALL) as opposed to a T-cell malignancy. Second, cloning and sequencing of the inversion revealed that it resulted from a fusion between an immunoglobulin heavy chain variable (V) segment and a T-cell receptor delta diversity (D) segment. In addition, the patient had a second chromosomal abnormality at diagnosis, a t(4;11)(q21;q23) which disrupted the MLL gene. The fact that there were two distinct chromosomal abnormalities at diagnosis enabled us to address the question of leukemic clonal evolution during the course of this patient's disease. We present evidence suggesting that the t(4;11)(q21;q23) occurred first, with the inv(14)(q11q32) occurring as a second event.