Philadelphia Chromosome-positive Acute Leukemia Research Articles

Novel third-generation tyrosine kinase inhibitor for newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia: a case study.

Although Philadelphia chromosome-positive acute leukemia (Ph + -ALL) has been revolutionized with tyrosine kinase inhibitors (TKIs), resistance and mutation are universal events during treatment with first-generation and second-generation TKIs. The present third-generation TKI has a dose-dependent, increased risk of serious cardiovascular events and the sensitivity is poor for patients with ≥2 mutations accompanied by the T315I mutation. Thus, novel and well-tolerated TKIs should be explored. This study analyzes the efficacy and advert effects of olverembatinib, a novel third TKI, in the treatment of newly diagnosed adult Ph + -ALL in induction therapy. Four adult patients with newly diagnosed Ph + -ALL were treated with olverembatinib as the first-line treatment. For induction therapy, these patients received 40 mg of oral olverembatinib quaque omni die for 28 days, 1 mg/kg/d of prednisone for 14 days, then tapered and stopped at 28 days and vindesine 4 mg/d at days 1, 8 and 15. After induction therapy, these patients received median or high-dose of cytarabine and methotrexate combined with oral olverembatinib as consolidation therapy. Then the allogeneic hematopoietic stem cell transplantation (allo-HSCT) was performed. All patients reached complete remission with a complete cytogenetic response after induction therapy. Two patients reached major molecular remission and one with complete molecular remission. Before allo-HSCT, all the patients achieved complete molecular remission. All the patients have survived disease-free for 3-6 months. No severe advert effects were observed. It is well-tolerated and effective for olverembatinib in the treatment of newly diagnosed adult patients with Ph + -ALL. A prospective study should be performed to further testify the role.

Dasatinib alone for treatment of relapsed/refractory philadelphia chromosome-positive acute leukemia sustained remission: report of two cases and review of literature

目的 探讨二代酪氨酸激酶抑制剂达沙替尼单药治疗复发难治费城染色体阳性（Ph+）急性白血病的临床效果。 方法 收集2015年2月和2016年2月郑州大学附属洛阳中心医院收治的应用达沙替尼单药治疗的2例复发难治Ph+急性白血病患者资料，分析其疗效和预后，并进行文献复习。 结果 2例患者均为男性，年龄分别为1、21岁。2例患者经达沙替尼单药巩固治疗后均获得完全缓解（CR），1例达CR后长期生存，1例CR 5个月后复发。 结论 达沙替尼单药巩固治疗Ph+急性白血病有较好的缓解效果，可延长患者生存时间。达沙替尼单药可作为未进行造血干细胞移植的Ph+急性白血病患者的巩固治疗方案。

Intrathecal Infusion of Haploidentical Nondonor Lymphocytes for Central Nervous System Leukemic Relapse After Haploidentical Hematopoietic Stem Cell Transplantation.

Leukemic relapse in the central nervous system (CNS) after conventional treatment is associated with a poor prognosis. The effectiveness and safety of IV infusion of human leukocyte antigen (HLA)-mismatched lymphocytes for leukemia, and intrathecal (IT) infusion of HLA-mismatched lymphocytes for cerebrospinal fluid (CSF) dissemination of medulloblastoma have been reported. A 13-year-old girl (HLA-A31) was diagnosed as relapsing from Philadelphia chromosome-positive acute leukemia in the CNS after receiving chemotherapy, tyrosine kinase inhibitors, haploidentical hematopoietic stem cell transplantation (HSCT) from her father (HLA-A31), and craniospinal irradiation. We performed an IT infusion of haploidentical lymphocytes from her mother. Peripheral blood mononuclear cells obtained from her mother (HLA-A31) were administered by IT infusion weekly. Examination of CSF 1 week after first IT showed that lymphocyte counts had increased markedly and the breakpoint cluster region/abelson-bearing cells had disappeared. Furthermore, CD3 T cells in the CSF were negative for HLA-A31, and expressed high HLA-DR. These results indicate the infused non-HSCT-donor lymphocytes did not survive, and that the HSCT donor(father)-derived lymphocytes migrated to the CSF and were activated. The patient showed partial remission for 2 months following this therapy. Serious adverse reactions and graft versus host disease were not observed. To control leukemic CNS dissemination, haploidentical nondonor lymphocytes might contribute to a graft versus leukemia effect.

High CFTR expression in Philadelphia chromosome-positive acute leukemia protects and maintains continuous activation of BCR-ABL and related signaling pathways in combination with PP2A.

Cystic fibrosis transmembrane conductance regulator (CFTR) is classified as an anion channel transporter of Cl− and HCO3−. Through interactions with its PDZ domain, CFTR is capable of regulating other proteins, such as protein phosphatase 2A (PP2A). The aberrant expression and mutation of CFTR have been observed in several tumor, but not in philadelphia chromosome–positive(Ph+) acute leukemia, including Ph+ B cell acute lymphoblastic leukemia(Ph+ B-ALL) and chronic myelogenous leukemia blast crisis phases (CML-BC). In this study, we demonstrated the mean expression level of CFTR in Ph+ acute leukemia cells was markedly higher than that in Ph- B-ALL and CML-chronic phase cells. CFTRinh-172, a classic CFTR inhibitor, down-regulated the expression of CFTR, p-BCR-ABL and classical Wnt/β-catenin signaling in Ph+ acute leukemia cells, while imatinib had no effect on CFTR. Importantly, reduced efficacy of CFTRinh-172 was closely associated with elevated PP2A phosphatase activity. Furthermore, we confirmed an interaction between CFTR and the PP2AA subunit in K562 cells. In addition, we demonstrated CFTR and PP2AA interact in the cytosol, resulting in PP2A complex inactivation and increased degradation of PP2A substrates via the lysosomal/proteasome pathway. In conclusion, our results showed CFTR was highly expressed in Ph+ acute leukemia, which protected and maintained the continuous activation of BCR-ABL and the canonical Wnt/β-catenin signaling pathway by decreasing PP2A phosphatase activity. According to this working model of the CFTR-PP2A-BCR-ABL axis, targeting the CFTR protein will activate PP2A and may offer a new treatment strategy for Ph+ acute leukemia, especially for patients exhibiting high levels of CFTR expression.

Pro-survival role of protein kinase C epsilon in Philadelphia chromosome positive acute leukemia

Durable responses to imatinib monotherapy are rarely seen in aggressive forms of Philadelphia chromosome positive (Ph+) leukemias. To investigate the possible cause of treatment failure we examined the role of protein kinase C epsilon (PKCE), an oncogene highly implicated in the development of solid tumors and resistance to chemotherapy. We found high levels of PKCE transcripts in Ph+ acute lymphoblastic leukemia (ALL) cells from patients and cell lines, and imatinib resistant chronic myeloid leukemia, which were also less responsive to imatinib-induced apoptosis than Ph+ cells with lower PKCE expression. Furthermore, the siRNA-mediated knockdown or peptide inhibition of PKCE in Ph+ cells increased imatinib-induced apoptosis while overexpression of PKCE reduced imatinib-induced apoptosis, with concomitant increase in the pro-survival factor AKT. Our results suggest PKCE plays a protective role against apoptosis induced by BCR-ABL inhibition in Ph+ leukemias with high PKCE expression, such as Ph+ ALL.

A TCR-mimic antibody to WT1 bypasses tyrosine kinase inhibitor resistance in human BCR-ABL+ leukemias

AbstractAcute and chronic leukemias, including CD34+ CML cells, demonstrate increased expression of the Wilms tumor gene 1 product (WT1), making WT1 an attractive therapeutic target. However, WT1 is a currently undruggable, intracellular protein. ESKM is a human IgG1 T-cell receptor mimic monoclonal antibody directed to a 9–amino acid sequence of WT1 in the context of cell surface HLA-A*02. ESKM was therapeutically effective, alone and in combination with tyrosine kinase inhibitors (TKIs), against Philadelphia chromosome–positive acute leukemia in murine models, including a leukemia with the most common, pan-TKI, gatekeeper resistance mutation, T315I. ESKM was superior to the first-generation TKI, imatinib. Combination therapy with ESKM and TKIs was superior to either drug alone, capable of curing mice. ESKM showed no toxicity to human HLA-A*02:01+ stem cells under the conditions of this murine model. These features of ESKM make it a promising nontoxic therapeutic agent for sensitive and resistant Ph+ leukemias.

The Outcomes Of Allogeneic Stem Cell Transplantation In Patients With Mixed Phenotype Acute Leukemia (MPAL) Are Comparable To Those In Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL): Results Of a Matched-Pair Analysis

BackgroundMPAL is a rare subtype of acute leukemia that accounts for 2-5% of all acute leukemia cases. It has been reported that patients with MPAL tend to have worse prognosis compared with those with AML or ALL. However, the efficacy and safety of allogeneic stem cell transplantation (allo-SCT) for adult MPAL patients has yet to be elucidated. ObjectiveThe aim of this retrospective study was to assess the outcomes of allo-SCT for adult MPAL and compared with those for AML/ALL using a matched pair analysis method. Patients and MethodsThis study included patients over 15 years of age who were diagnosed with MPAL according to the WHO classification and underwent allo-SCT for the first time between January 2001 and December 2010. Their clinical data were collected from the database of the Kanto Study Group for Cell Therapy. The clinical features and transplant outcomes of MPAL patients were then compared with those of adult patients with AML, ALL, and Philadelphia chromosome-positive acute leukemia (Ph+AL). We selected control cohorts at the rate of one to five using an optimal matching method with the following seven matching factors: age, sex, disease status at the time of transplant, the intensity of conditioning, human leukocyte antigen disparity between donor and recipient, donor type (related or not), and time of transplant (2001-2005 or 2006-2010). Overall survival (OS) and relapse-free survival (RFS) rates was estimated by the Kaplan-Meier method and compared using the log-rank test. Cumulative incidences (CI) of relapse and non-relapse mortality (NRM) were compared using the stratified Gray test. P <0.05 was considered to represent statistical significance. ResultsEighteen MPAL patients (9 men, 9 women) with a median age of 40 years (range, 16–61 years) were identified. Immunophenotypic analysis showed B+M phenotype in 12 patients, B+T phenotype in five, and B+T+M phenotype in one. Seven patients possessed Ph. Fourteen patients were in remission at the time of transplant. Sixteen patients were conditioned with myeloablative regimens. Stem cell sources were related donor bone marrow in four patients, unrelated donor bone marrow in 13, and cord blood in one. Among 18 MPAL patients, 5-year OS and RFS rates were 48.1% and 39.7%, respectively, and 5-year CI of relapse and NRM were 43.3% and 17.1%, respectively. Patients in remission at the time of transplant showed significantly better outcomes than those not in remission (5-year OS: 71.8% vs. 0%, p = 0.001; 5-year RFS: 58.7% vs. 0%, p = 0.004). By contrast, no significant difference was seen in OS and RFS when stratifying patients according to immunophenotype and cytogenetic abnormalities. In matched pair analysis, 90 AML, 90 ALL, and 35 Ph+AL patients were extracted from the database as control. The 5-year OS rate of MPAL patients was similar to those of AML patients (48.1% vs. 48.1%; p = 0.855) and ALL patients (48.1% vs. 37.8%; p = 0.426). Similarly, the 5-year OS rate of Ph+MPAL patients was not significantly different from that of Ph+AL patients (68.6% vs. 39.9%; p = 0.234). No significant difference was observed in RFS, CI of relapse, and CI of NRM when comparing MPAL patients with AML and ALL patients, and Ph+MPAL patients with Ph+AL patients. ConclusionTransplant outcomes of adult MPAL patients were comparable to those of both AML and ALL patients, although the statistical power was possibly insufficient due to the relatively small cohort. The existing transplant procedures were not satisfactory for MPAL patients who were not in remission at the time of transplant. On the other hand, MPAL patients who underwent allo-SCT while in remission showed excellent outcomes. Therefore, transplant early in the disease course may lead to improved outcomes for patients with this serious disease. Disclosures:No relevant conflicts of interest to declare.

Severe hemorrhagic colitis in a patient with chronic myeloid leukemia in the blastic phase after dasatinib use

Dasatinib is a second-line tyrosine kinase inhibitor used in patients with imatinib resistant or intolerant chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute leukemia. Gastrointestinal bleeding may occur in up to 7% of patients using dasatinib, although, severe dasatinib-related acute colitis had rarely been reported. Here, we present the case of a 36-year-old female who progressed to acute myeloid leukemia after fourteen months of receiving imatinib for CML in the chronic phase and was treated with a dasatinib-containing chemotherapy regimen. On day 34 of treatment, the patient developed moderate abdominal pain and bloody diarrhea with mucous. Analyses of stool specimens were negative for parasites, Clostridium difficile, and other pathogenic bacteria. The cytomegalovirus pp65 antigen was negative in her blood leukocytes. A colonoscopy revealed acute colitis, and a mucosal biopsy showed nonspecific colitis. The patient was treated with broad-spectrum antibiotics, bowel rest and hydration, and dasatinib treatment was stopped. Her bloody diarrhea improved within 72 h. After confirming cytological remission, the patient received initial course of consolidation, and dasatinib treatment was reinstated. However, hemorrhagic colitis recurred. After discontinuing dasatinib, herhemorrhagic colitis drastically improved and did not recur following the administration of nilotinib. The characteristics of our patient suggest that dasatinib treatment can lead to hemorrhagic colitis, which typically resolves after discontinuation of the drug.

Clinical Significance of Mixed Phenotype in Adult Patients with Philadelphia Chromosome-Positive Acute Leukemia–no Prognostic Impact in the Imatinib Era.

Abstract 2574 Background:Mixed phenotype acute leukemia (MPAL) has historically been known as biphenotypic acute leukemia (BAL), and novel diagnostic criteria for this disease entity are described in the World Health Organization (WHO) classification 4th edition. As the most common recurrent genetic abnormality observed in MPAL is the bcr-abl fusion gene, Philadelphia chromosome-positive MPAL (Ph+MPAL) has been recognized as one distinctive disease entity. The prognosis of Ph+B-cell acute lymphoblastic leukemia (Ph+B-ALL) has been dramatically improved with the introduction of imatinib, and the goal of this study was to determine whether imatinib results in a survival benefit in the context of Ph+MPAL. Patients and Methods:We retrospectively analyzed 42 consecutive adult patients who were diagnosed with Ph+AL between January 2001 and March 2012 at Gunma University Hospital and Saiseikai Maebashi Hospital in Gunma, Japan. Ph+AL was diagnosed based on detection of the bcr-abl fusion gene with the polymerase chain reaction method and the presence of more than 20% of blasts in the peripheral blood and/or bone marrow. Patients with a previous history of chronic myelogenous leukemia were excluded. The lineage of leukemia cells was defined according to the WHO classification 4th edition. All patients received intensive chemotherapy and concurrent administration of imatinib. The c2-test was used for comparison of binary variables. The Mann-Whitney U test was used for comparison of continuous variables. Overall survival (OS) rate was estimated by the Kaplan-Meier method and were compared using the log-rank test. P < 0.05 was considered as statistically significant. Results:According to the WHO classification 4th edition, 13 (31%) patients were categorized as Ph+MPAL (positive for both myeloid and B-cell lineage), 27 (64%) patients were categorized as B-cell lineage acute lymphoblastic leukemia (Ph+B-ALL), and two (5%) patients were categorized as acute myeloid leukemia (Ph+AML). Patients with Ph+AML were excluded from this study, as the number of patients was relatively small. Of the 40 Ph+AL patients, 23 patients were men, and 17 were women, and the median age was 53 years (range, 16–75 years). Age, sex, white blood cell counts, lactate dehydrogenase levels, and the prevalence of additional cytogenetic abnormalities at diagnosis were not significantly different when comparing the groups, although patients with Ph+MPAL showed significantly higher frequency of major bcr-abl gene than those with Ph+B-ALL (69% and 19%, respectively; p < 0.01). Immunophenotypic analysis revealed that Ph+MPAL patients expressed CD10 and CD34 with significantly lower frequency than Ph+B-ALL patients. Notably, positivity of myeloid antigens (CD13 and 33) was similar between both groups. The complete response (CR) rates after the initial induction therapy were not significantly different when comparing Ph+MPAL and Ph+B-ALL (100% vs. 85%, respectively, p = 0.14). Likewise, the 5-year-OS rate was similar when comparing patients with Ph+MPAL and Ph+B-ALL (55% vs. 53%, respectively, p = 0.87). Of the 13 patients with Ph+MPAL, six patients received AML-type chemotherapy, and seven patients received ALL-type chemotherapy as the initial induction therapy. All patients achieved CR after the initial induction therapy, and there was no significant difference in 5-year OS according to the therapeutic strategy (AML-type vs. ALL-type), (50% vs. 63%, respectively, p = 0.71). Among 12 patients younger than 65 years old who were alive at >3 months after the diagnosis, eight patients underwent allogeneic hematopoietic stem cell transplantation (allo SCT). The 5-year OS was significantly better for patients who underwent allo-SCT than for those who received chemotherapy alone (58% vs. 20%, respectively, p = 0.05). Conclusion:Among adult Ph+AL patients, mixed phenotype was more frequently observed than expected, and Ph+MPAL patients showed unique clinical features, including immunophenotype and the type of bcr-abl fusion gene. Although BAL has been considered as a negative prognostic factor, Ph+MPAL patients showed comparable prognosis to those with Ph+B-ALL who received imatinib-containing intensive chemotherapy. Therefore, the established theory that mixed phenotype is associated with poor outcomes should be revisited among these patients. Disclosures:No relevant conflicts of interest to declare.

High-dose imatinib mesylate combined with vincristine and dexamethasone (DIV regimen) as induction therapy in patients with resistant Philadelphia-positive acute lymphoblastic leukemia and lymphoid blast crisis of chronic myeloid leukemia

Imatinib combined with high-dose chemotherapy is now becoming the gold standard for treatment of Philadelphia chromosome-positive acute leukemias. However, in all studies imatinib dosage was tapered to 400-600 mg per day. We decided to initiate a clinical trial to evaluate an opposite strategy based on high-dose imatinib (800 mg per day) combined with a less intensive chemotherapeutic regimen (vincristine and dexamethasone), which we called the DIV induction regimen. Thirty-one patients (18 relapsing or refractory Ph+ acute lymphoblastic leukemias and 13 lymphoid blast crisis chronic myelogenous leukemias) were enrolled. Complete remission (CR) was obtained in 28 out of 30 assessable patients. The median bcr-abl/abl ratio after the induction course was 0.1%. Median time to neutrophil recovery was 21 days. Fungus infections were observed in six patients out of 31 and possibly related to dexamethasone. Neuropathy due to vincristine was noted in 14 cases. Nine out of 19 patients under 55 years received allogenic stem cell transplantation after a median time of 78 days post-CR. Patients older than 55 years experienced a 90% CR rate without additional toxicities, suggesting the DIV regimen may also be proposed as a front line therapy in older patients.

Quantitative real-time reverse-transcription polymerase chain reaction for diagnosis of BCR-ABL positive leukemias and molecular monitoring following allogeneic stem cell transplantation.

Real-time reverse-transcription polymerase chain reaction (RT-PCR) (qPCR) of the BCR-ABL mRNA is a suitable technique to measure the amount of circulating leukemic cells in chronic myelogenous leukemia (CML). In this study, we evaluated a BCR-ABL-specific qPCR method using the LightCycler technology in 95 patients with Philadelphia chromosome positive acute leukemia (n = 7) or CML in different stages (n = 88). Primers and hybridization probes were chosen to detect the most prevalent variants of BCR-ABL (b2a2, b3a2, b2a3, b3a3, e19a2, e1a2) with a sensitivity of 10-5 for b2a2 and b3a2. With median BCR-ABL/G6PDH ratios of 10.7% in the untreated chronic phase, 43.2% in the newly diagnosed accelerated phase, and 131.4% in newly diagnosed blast crisis the BCR-ABL mRNA levels varied significantly between different stages of CML whereas no difference was found between blast crisis and untreated acute leukemias (136.9%). There was a strong relationship between qPCR results and cytogenetics in patients treated with imatinib, interferon-alpha, or following allografting. Thirteen patients with CML were sequentially examined by qPCR following myeloablative or non-myeloablative allogeneic peripheral blood stem cell transplantation. Five patients received donor lymphocytes and became BCR-ABL negative as confirmed by nested RT-PCR. The gradual disappearance of BCR-ABL positive cells could be monitored by qPCR following non-myeloablative transplantation. Comparison of BCR-ABL levels with the degree of donor chimerism showed that 91% of samples with complete donor chimerism were BCR-ABL negative. In 22% of BCR-ABL negative samples chimerism between 71% and 98% was observed, indicating the persistence of normal recipient's hematopoietic cells. In conclusion, the qPCR protocol used in this study is a reliable and fast method for monitoring molecular response in CML.

Participation of granulocyte colony-stimulating factor in the growth regulation of leukemia cells from Philadelphia chromosome-positive acute leukemia and blast crisis of chronic myeloid leukemia.

Granulocyte colony-stimulating factor (G-CSF) has been shown to support the growth of multipotential hematopoietic stem cells in addition to the cells of neutrophilic lineage. Philadelphia chromosome (Ph1)-positive leukemia has its origin in the hematopoietic stem cell. In the present study, we demonstrated that the proliferation of leukemic cells from chronic myeloid leukemia in blast crisis (CML-BC) and Ph1-positive acute lymphoblastic leukemia (ALL) cases is frequently stimulated with G-CSF in vitro. We next studied a total of 12 leukemic cell lines established from CML-BC (n= 6) and Ph1-positive acute leukemia (n= 6): four 'myeloid', five 'biphenotypic', and three 'lymphoid' types. All cell lines expressed G-CSF receptor (G-CSFR) in flow cytometric analysis, but their proliferative response to G-CSF in 3H-thymidine incorporation assay varied. The 'biphenotypic' cell lines expressed G-CSFR at higher levels and showed the most pronounced response to G-CSF. The 'lymphoid' cell lines showed intermediate G-CSFR expression with the modest response to G-CSF. Unexpectedly, 'myeloid' cell lines showed lower G-CSFR expression and lower G-CSF response compared with 'biphenotypic' cell lines. In three of four 'myeloid' cell lines, proliferation was partially inhibited by an addition of anti-G-CSF neutralizing monoclonal antibody into culture medium. Further, the % inhibition of 3H-thymidine uptake of cell lines positively correlated with the amount of their intracellular G-CSF measured by enzyme immunoassay, suggesting an autocrine growth mechanism via the G-CSF/G-CSFR interaction. These results suggest that G-CSF play an important role in the growth regulation of leukemia cells from Ph1-positive acute leukemia and CML-BC.

Biologic heterogeneity in Philadelphia chromosome-positive acute leukemia with myeloid morphology: the Eastern Cooperative Oncology Group experience.

Evaluable karyotypes were available in 776 of 1148 adult patients who were entered on acute myeloid leukemia (AML) treatment protocols of the Eastern Cooperative Oncology Group. Among these, we found seven patients (0.9%) with t(9;22)(q34;q11), the Philadelphia (Ph) chromosome, in bone marrow metaphases. All fulfilled the FAB criteria for AML (three M0, two M1, two M2), although one patient presented with an additional, distinct lymphoid blast cell population. Chromosomal aberrations in addition to the Ph chromosome were seen in four patients (including two cases of monosomy 7). Molecular analysis by polymerase chain reaction in four patients tested revealed variable BCR/ABL transcript forms (ela2, b2a2, b3a2, b2a3+ela2). By immunophenotyping, all seven patients were myeloid based on the overall antigen expression pattern. However, all but one demonstrated lymphoid-associated antigens on the myeloid blast cells. The six evaluable patients failed to respond to treatment with a standard anthracycline/cytosine arabinoside-containing regimen. We conclude that the incidence of the Ph chromosome in AML is very low. Although both genotypically and phenotypically heterogenous, Ph chromosome-positive AML, represents a clinically distinct entity with poor outcome.

Significance of the P210 versus P190 molecular abnormalities in adults with Philadelphia chromosome-positive acute leukemia

We investigated the significance of p210 and p190 molecular abnormalities in 32 adults with Philadelphia chromosome (Ph)-positive acute leukemia. p210 was detected in 15 patients (47%), p190 in 16 (50%), and both in one (3%). p210 was noted in 11 of 24 patients (46%) with acute lymphocytic leukemia, and in four of eight patients (50%) with acute myelogenous or undifferentiated leukemia. Among 29 patients with untreated disease (p210, 14 patients; p190, 15 patients), no significant differences in the two molecularly distinct groups were observed by pretreatment characteristics including age, degree of organomegaly, anemia, leukocytosis, thrombocytopenia, occurrence of karyotypic abnormalities in addition to Ph, or residual diploid metaphases. Complete response (CR) rates were also similar. Although the remission duration tended to be longer with p190 (P = .08), the differences were minor (median duration 29 v 20 weeks) and not paralleled by differences in survival rate. In 10 patients studied by karyotypic analysis in remission, two of four patients with p190 and two of six patients with p210 showed 100% normal metaphases. One of the seven patients (14%) with p210 who achieved CR manifested a morphologic picture of second chronic-phase chronic myelogenous leukemia lasting for 1 month. We conclude that the molecular studies in Ph-positive acute leukemia are not associated with significantly different clinico- laboratory, karyotypic, or prognostic implications.

Immunogenotypic and Clonal Culture Studies in Philadelphia Chromosome-positive Acute Leukemia

Immunogenotypic and Clonal Culture Studies in Philadelphia Chromosome-positive Acute Leukemia

Rearrangement of the breakpoint cluster region in Philadelphia chromosome positive acute leukemia.

The rearrangement of breakpoint cluster region (ber) was examined in leukemic cells obtained from 3 patients initially diagnosed as having Ph+ acute leukemia, 2 with acute lymphocytic leukemia (ALL) and one with acute mixed leukemia. DNA was digested with Bgl II and BamH I. The ber rearrangement was present in the case of acute mixed leukemia (Case 1), but was absent in the 2 cases of ALL (Cases 2 and 3). These results suggest that Case 1 represented a type of blast crisis of chronic myelocytic leukemia which was unusual in the sense of the occurrence of a myeloid-lymphoid conversion and lack of an apparent chronic phase. Cases 2 and 3 appeared to be de novo Ph+ ALL.

Phenotypic and Molecular Heterogeneity in Philadelphia Chromosome-Positive Acute Leukemia

Philadelphia chromosome-positive (Ph1) acute leukemia is a heterogeneous subset of acute leukemia with a poor prognosis. We studied five patients to determine the potential for phenotypic and molecular heterogeneity. Cellular characterization studies included light myeloperoxidase (L-MPO), terminal deoxynucleotidyl transferase (TdT), ultrastructural MPO (U-MPO), and immunophenotyping by flow cytometry using T11, T3, T4, T8, Leu 1, B1, Leu 12, HLA-DR (la), CALLA (J5), OKM1, My4, My7, My8, My9, and My10. DNA was analyzed for rearrangements of the breakpoint cluster region (bcr), immunoglobulin heavy chain, joining region (JH), immunoglobulin kappa light chain constant region (C kappa), and T cell receptor (TcR beta). RNA dot blots were hybridized by using molecular probes for MPO and TdT. We found that four of five cases were acute mixed-lineage leukemia (AMLL). One patient had acute unclassifiable leukemia. Of the four patients classified as having AMLL, three showed myeloid and lymphoid features, with one patient showing myeloid, T cell, and B cell features. The last case showed T cell and B cell features only. In one patient MPO/RNA was positive in spite of insufficient L-MPO or U-MPO to diagnose acute myelogenous leukemia (AML), thereby suggesting significant MPO gene expression before the production of sufficient MPO protein to meet the French-American-British criteria for AML. Three of the five patients showed rearrangement of bcr (cases 1, 2, and 5). Studies of these five patients support the concepts of molecular and phenotypic heterogeneity in Ph1 acute leukemia, demonstrate a high incidence of AMLL in this subset of acute leukemia, and support the use of lineage-associated molecular probes to define lineage at an earlier stage than previously possible.