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Assisted reproductive technology is a viable option for pregnant women with chronic myeloid leukemia. We herein report the case of a patient who underwent successful fertility treatment with frozen embryo preservation at 36 years of age, followed by embryo transfer at 39 years of age, thus resulting in pregnancy and delivery after a third discontinuation of tyrosine kinase inhibitors (TKIs). Despite the difficulty of long-term TKI withdrawal, the patient's strong desire for a baby led to a successful pregnancy and delivery with no apparent deformities or abnormalities. Thus, our case highlights the importance of collaboration between reproductive medicine physicians and hematologists.

Abstract: Deep molecular response (DMR) is a prerequite for treatment-free remission (TFR) in chronic myeloid leukemia in chronic phase (CML-CP). The JALSG (Japan Adult Leukemia Study Group) conducted a prospective randomized phase 3 CML212 study for de novo CML-CP to compare the cumulative achievement of molecular response 4.5 (MR4.5; international scale BCR::ABL1 ≤0.0032%) by 18 months between nilotinib and dasatinib treatment as a primary end point. A total of 454 patients were randomly assigned to the 300 mg nilotinib twice daily arm or to the 100 mg dasatinib daily arm (both n = 227). BCR::ABL1 messenger RNA levels were monitored every 3 months. Study treatment was stopped if the patients were judged as failure according to the European LekemiaNet 2009 criteria or showed intolerance. The cumulative achievement rates of MR4.5 by 18 months were 32.6% (95% confidence interval [CI], 26.5-39.1) in the nilotinib arm and 30.8% (95% CI, 24.9-37.3) in the dasatinib arm with no significant difference (P = .66). The cumulative achievement rates of early molecular response, complete cytogenetic response, and major molecular response by 12, 18, 24, and 36 months were almost the same between the 2 arms. There was no significant difference in progression-free survival (PFS) or overall survival (OS) between the 2 arms by log-rank tests (PFS, P = .58; OS, P = .64). These results suggest that nilotinib and dasatinib would be equally effective for patients with de novo CML-CP. This trial was registered in the University Hospital Medical Information Network Clinical Trials Registry as #UMIN000007909., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

The Philadelphia (Ph) chromosome was the first translocation identified in leukemia. It is supposed to be generated by aberrant ligation between two DNA double-strand breaks (DSBs) at the BCR gene located on chromosome 9q34 and the ABL1 gene located on chromosome 22q11. Thus, mimicking the initiation process of translocation, we induced CRISPR/Cas9-mediated DSBs simultaneously at the breakpoints of the BCR and ABL1 genes in a granulocyte-macrophage colony-stimulating factor (GM-CSF) dependent human leukemia cell line. After transfection of two single guide RNAs (sgRNAs) targeting intron 13 of the BCR gene and intron 1 of the ABL1 gene, a factor-independent subline was obtained. In the subline, p210 BCR::ABL1 and its reciprocal ABL1::BCR fusions were generated as a result of balanced translocation corresponding to the Ph chromosome. Another set of sgRNAs targeting intron 1 of the BCR gene and intron 1 of the ABL1 gene induced a factor-independent subline expressing p190 BCR::ABL1. Both p210 and p190 BCR::ABL1 induced factor-independent growth by constitutively activating intracellular signaling pathways for transcriptional regulation of cell cycle progression and cell survival that are usually regulated by GM-CSF. These observations suggested that simultaneous DSBs at the BCR and ABL1 gene breakpoints are initiation events for oncogenesis in Ph+ leukemia. (200/200 words)., (© 2022. The Author(s).)

Bosutinib has been evaluated for treatment of chronic-phase chronic myeloid leukemia (CP-CML) in several clinical studies, including in Japan. This open-label, single-arm, phase 2 study evaluated the efficacy and safety of bosutinib at a starting dose of 400 mg once daily in Japanese patients (n = 60) with newly diagnosed CP-CML. The minimum follow-up period was 3 years and median duration of treatment was 35.9 months. At study completion, 60% of patients were still on treatment. Cumulative rates of major molecular response (MMR), molecular response 4 (MR 4 ), and MR 4.5 at any time were 70.0%, 53.3%, and 48.3%, respectively. No patient who achieved MMR or MR 4 had a confirmed loss of response. No patient experienced on-treatment transformation to accelerated/blast phase or died within 28 days of the last bosutinib dose. Any-grade treatment-emergent adverse events (TEAEs) occurred in 100% (grade ≥ 3: 81.7%) of patients. The most common TEAEs were diarrhea (86.7%), increased alanine aminotransferase (55.0%), and increased aspartate aminotransferase (46.7%). No new safety signals emerged during the follow-up period. Bosutinib continues to demonstrate a favorable benefit/risk profile and is an important treatment option for Japanese patients with newly diagnosed CP-CML. Optimal management of TEAEs during initial treatment with bosutinib should be prioritized.Trial Registration: ClinicalTrials.gov ID: NCT03128411., (© 2022. The Author(s).)

Right neck swelling and pain occurred in a 49-year-old man. A Blood count showed a slight increase in platelet count without leukemoid reaction. After a biopsy of the cervical mass and bone marrow aspiration, a diagnosis of extramedullary blast crisis (EBC) of chronic myeloid leukemia (CML) was made. Fluorescence in situ hybridization (FISH) analysis showed a BCR-ABL1 fusion signal, but results of real-time polymerase chain reaction (RT-PCR) for major and minor BCR-ABL1 transcripts were negative. We identified a rare e1a3 BCR-ABL1 fusion transcript. Administration of dasatinib resulted in disappearance of the extramedullary tumor. This is the first reported case of CML-EBC with e1a3 transcript. An aleukemic extramedullary tumor can be the initial presentation of CML.

A 21-year-old woman was diagnosed with chronic myeloid leukemia in March 2014. The patient and her family did not wish to freeze eggs before dasatinib initiation. After 66 months of oral dasatinib administration and 40 months of MR4.5 maintenance, the patient requested to discontinue dasatinib due to a desire to conceive. MR4.5 maintenance was continued, and she achieved spontaneous pregnancy 6 months after dasatinib discontinuation. The patient gave birth to a normal baby 13 months later and was on MR4.5 maintenance 21 months after dasatinib discontinuation.

This study reports two cases of dasatinib-associated lymphadenopathy (DAL). Case 1 involved a 58-year-old man diagnosed with chronic myelogenous leukemia (CML). After 13 months of starting on dasatinib treatment, a molecular response (MR) 4.5 was achieved. Due to the loss of MMR, dasatinib was discontinued at 39 months but restarted at 42 months. Right cervical lymphadenopathy appeared 51 months after starting the treatment. DAL was diagnosed based on the findings of a cervical lymph node biopsy. After dasatinib was switched to ponatinib, the lymphadenopathy disappeared without recurrence. In case 2, a 54-year-old man was diagnosed with CML. He was started on dasatinib and MR 4.5 was achieved after 6 months. Left cervical lymph node adenopathy appeared 21 months later, and a diagnosis of DAL was made based on the findings of a cervical lymph node biopsy. After discontinuation of dasatinib, cervical lymph node adenopathy disappeared without recurrence. The possibility of DAL should be considered if lymphadenopathy is observed during dasatinib treatment.

Chronic myeloid leukemia (CML) is a form of myeloproliferative neoplasm caused by the oncogenic tyrosine kinase BCR-ABL. Although tyrosine kinase inhibitors have dramatically improved the prognosis of patients with CML, several problems such as resistance and recurrence still exist. Immunological control may contribute to solving these problems, and it is important to understand why CML patients fail to spontaneously develop anti-tumor immunity. Here, we show that differentiation of conventional dendritic cells (cDCs), which are vital for anti-tumor immunity, is restricted from an early stage of hematopoiesis in CML. In addition, we found that monocytes and basophils, which are increased in CML patients, express high levels of PD-L1, an immune checkpoint molecule that inhibits T cell responses. Moreover, RNA-sequencing analysis revealed that basophils express genes related to poor prognosis in CML. Our data suggest that BCR-ABL not only disrupts the "accelerator" (i.e., cDCs) but also applies the "brake" (i.e., monocytes and basophils) of anti-tumor immunity, compromising the defense against CML cells., (© 2021. The Author(s).)

Nilotinib is widely used for primary treatment of patients with chronic myelogenous leukemia (CML). We previously reported that use of an FRET-based drug sensitivity test at diagnosis efficiently predicts the response to treatment with imatinib or dasatinib. Here, we conducted a phase-II study to evaluate the efficacy and safety of nilotinib treatment and identify useful biomarkers, including results of the FRET-based drug sensitivity test, for predicting treatment response. Data from 42 patients were used in the analysis. Major molecular response (MMR), MR4, and MR4.5 rates at 12 months were 64.3, 42.9, and 28.6%, respectively. Grade 3/4 non-hematologic adverse events occurred in 11 patients (26.2%). The dose intensity of nilotinib (> 76.44%) and halving time (HT, < 13.312 days) were identified as significant factors for MMR at 12 months. However, when we focused on patients whose dose intensity of nilotinib was > 76.44%, the FRET-based drug sensitivity test became a predictive factor of MR4 achievement at 12 months. Our study reconfirmed the efficacy and safety of nilotinib treatment in CML patients. Moreover, our results suggest that the FRET-based drug sensitivity test is an independent predictor for achievement of MR4 in patients treated with a sufficient dose intensity of nilotinib.

Background: Treatment-free remission (TFR), the ability to maintain a molecular response (MR), occurs in approximately 50% of patients with chronic myelogenous leukemia (CML) treated with tyrosine kinase inhibitors (TKIs)., Methods: A multicenter phase 2 trial (Delightedly Overcome CML Expert Stop TKI Trial: DOMEST Trial) was conducted to test the safety and efficacy of discontinuing imatinib. Patients with CML with a sustained MR of 4.0 or MR4.0-equivalent for at least 2 years and confirmed MR4.0 at the beginning of the study were enrolled. In the TFR phase, the international scale (IS) was regularly monitored by IS-PCR testing. Molecular recurrence was defined as the loss of MR4.0. Recurrent patients were immediately treated with dasatinib or other TKIs including imatinib., Results: Of 110 enrolled patients, 99 were evaluable. The median time from diagnosis to discontinuation of imatinib was 103 months, and the median duration of imatinib therapy was 100 months. Molecular recurrence-free survival rates were 69.6%, 68.6% and 64.3% at 6, 12, and 24 months, respectively. After discontinuation of imatinib therapy, 26 patients showed molecular recurrence, and 25 re-achieved deep MR after dasatinib treatment. Molecular response MR4.0 was achieved in 23 patients within 6 months and 25 patients within 12 months. Multivariate analysis revealed that a longer time from diagnosis to discontinuation of imatinib therapy (p = 0.0002) and long duration of imatinib therapy (p = 0.0029) predicted a favorable prognosis., Conclusions: This DOMEST Trial showed the feasibility of TKI discontinuation in a Japanese clinical setting.

We evaluated the effects of regulatory T cell (Treg) inhibition during dasatinib treatment on the anticancer immune response, particularly on natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). Fifty-two newly diagnosed Japanese patients with chronic myeloid leukemia (CML) in the chronic phase were enrolled in the D-first study; all received 100 mg of dasatinib once daily and were followed for at least 36 months. The cumulative deep molecular response (DMR, MR4) rate was 65% by 36 months; the 3-year overall survival was 96%. CD4 + T cell counts were stable, whereas the proportion of CD4 + CD25 + CD127 low (Treg) cells decreased in a time-dependent manner. The DMR rate by18 months was significantly better in low Treg patients (<5.7% at 12 months) compared to the remaining patients (odds ratio 4.07). NK cell and CTL counts at several time points were inversely correlated with Treg counts. Furthermore, the degree of NK cell differentiation (CD3 - CD57 + /CD3 - CD56 + ) was closely and inversely correlated with the proportion of Treg cells throughout the observation period, and showed a gradually increasing trend. In conclusion, our results demonstrate that Treg inhibition by dasatinib contributes to better treatment response through enhancement of the immune system, particularly via NK cell differentiation., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The international phase III DASISION trial demonstrated improved efficacy of dasatinib versus imatinib in treatment-naive patients with chronic myeloid leukemia in the chronic phase (CML-CP). We report efficacy and safety outcomes in a Japanese population from the final, 5-year follow-up of DASISION. At the end of the study, 77% (20/26) of dasatinib-treated and 61% (14/23) of imatinib-treated patients remained on initial therapy. Improved responses were observed in Japanese patients who received dasatinib versus imatinib (complete cytogenetic response: 96 vs 87%; major molecular response: 88 vs 74%; BCR-ABL1 ≤0.0032% International Scale [MR 4.5 ]: 58 vs 52%). In patients who achieved BCR-ABL1 ≤10% at 3 months, 5-year progression-free survival and overall survival rates were high with dasatinib (96 and 96%) and imatinib (88 and 100%). The majority of adverse events were grade 1/2 in Japanese patients. Pleural effusion occurred more frequently in dasatinib-treated Japanese patients versus all patients (42 vs 28%), with no treatment discontinuations. Overall, in Japanese patients, dasatinib maintained its safety profile and had higher or comparable response and survival outcomes compared with imatinib or with all patients in DASISION. These findings demonstrate the long-term efficacy and tolerability of dasatinib and support frontline treatment of Japanese patients with CML-CP with dasatinib.

Although tyrosine kinase inhibitors (TKIs) have significantly improved the prognosis of chronic myeloid leukemia (CML), the ability of TKIs to eradicate CML remains uncertain and patients must continue TKI therapy for indefinite periods. In this study, we performed whole-exome sequencing to identify somatic mutations in 24 patients with newly diagnosed chronic phase CML who were registered in the JALSG CML212 study. We identified 191 somatic mutations other than the BCR-ABL1 fusion gene (median 8, range 1-17). Age, hemoglobin concentration and white blood cell counts were correlated with the number of mutations. Patients with mutations ⩾6 showed higher rate of achieving major molecular response than those<6 (P=0.0381). Mutations in epigenetic regulator, ASXL1, TET2, TET3, KDM1A and MSH6 were found in 25% of patients. TET2 or TET3, AKT1 and RUNX1 were mutated in one patient each. ASXL1 was mutated within exon 12 in three cases. Mutated genes were significantly enriched with cell signaling and cell division pathways. Furthermore, DNA copy number analysis showed that 2 of 24 patients had uniparental disomy of chromosome 1p or 3q, which disappeared major molecular response was achieved. These mutations may play significant roles in CML pathogenesis in addition to the strong driver mutation BCR-ABL1.

We present a 36-year-old woman who had been taking oral dasatinib for 3 years for the treatment of chronic myelogenous leukemia (CML). Although adverse events such as thrombocytopenia and pleural effusion developed, she showed a major molecular response (MMR) 22 months after the initiation of oral dasatinib administration, and the therapy was thus continued. Approximately 34 months after oral dasatinib initiation, she developed severe exertional dyspnea and had to be urgently hospitalized. There was no apparent pleural effusion increase, and neither imaging nor blood test results suggested pneumonia or other infections. Pulmonary arterial hypertension (PAH) was suspected on the basis of transthoracic echocardiography. PAH was then confirmed by right heart catheterization. Though dasatinib was discontinued on the day of hospitalization, pulmonary hypertension and heart failure progressed, and she did not respond to catecholamines or PDE5 (phosphodiesterase type 5) inhibitors. On the 4(th) hospital day, she experienced cardiopulmonary arrest and died 1 week later. Cases with PAH due to oral administration of dasatinib have been reported previously. However, cases showing the rapid progression documented in our patient are rare and we advocate that PAH be considered a potential adverse event associated with dasatinib therapy.

To investigate the factors that affect molecular responses on dasatinib treatment in patients with chronic-phase chronic myeloid leukemia (CML-CP), we performed a clinical trial named the "D-First study." Fifty-two patients with newly diagnosed CML-CP were enrolled in this study and received 100 mg dasatinib once daily. A deep molecular response (DMR) was defined as <50 copies/μg RNA of BCR-ABL1 transcript value corrected by GAPDH, which ensures <0.01% of BCR-ABL1 transcript value according to International Scale (BCR-ABL1(IS)). The halving time for BCR-ABL1 transcripts was calculated using transcript levels before dasatinib treatment, transcript levels after 3 months of treatment, and the treatment time between these two points. In terms of molecular response, 38 of 51 (75%) patients reached major molecular response (MMR) by 12 months, and the rate of DMR by 18 months was 59% (30/51). While both BCR-ABL1 transcript levels before treatment and a shorter halving time of BCR-ABL1 transcripts (≤14 days) were significant factors affecting achievement of MMR by 12 months, the Sokal score at diagnosis was not associated with MMR. Importantly, the halving time was the only factor that predicted achievement of DMR by 18 months. We showed that patients with CML-CP treated with dasatinib can be stratified according to the early treatment response as determined by the halving time of BCR-ABL1 transcripts. These data emphasize the significance of the early response from dasatinib treatment in achieving a DMR. (ClinicalTrials.gov; NCT01464411)., (© 2014 Wiley Periodicals, Inc.)

Dasatinib is a BCR-ABL kinase inhibitor with improved potency compared with imatinib, for which efficacy and safety in imatinib-resistant and imatinib-intolerant patients with chronic myelogenous leukemia (CML) have been established. Here, an open-label phase II study evaluated the efficacy and safety of dasatinib in 50 Japanese patients with imatinib-resistant or imatinib-intolerant CML during the chronic phase (CML-CP). Dasatinib was effective in imatinib-resistant and imatinib-intolerant patients. After 12 months of dasatinib therapy, 35 patients (70%) had achieved a major molecular response (MMR) and 16 patients (32%) had achieved a complete molecular response (CMR). Among the imatinib-resistant CML-CP cohort, 21 and 8 patients had achieved an MMR and a CMR after 12 months of dasatinib therapy, respectively. Among the imatinib-intolerant CML-CP cohort, 14 and 8 patients had achieved an MMR and a CMR after 12 months of dasatinib therapy, respectively. After 18 months of dasatinib therapy, 38 out of 50 patients (76.0%) had achieved an MMR and 19 patients (38.0%) had achieved a CMR. A lower level of BCR-ABL transcript at 1 or 3 months after the initiation of dasatinib treatment was more strongly correlated with the BCR-ABL transcript level at 12 and 18 months (p ＜ 0.001) than a higher level of BCR-ABL. The T315I mutation was identified in two patients receiving dasatinib therapy. Dasatinib was generally well tolerated, with only 3 patients (5%) having treatment discontinuation as a result of adverse hematologic events (thrombocytopenia, anemia, neutropenia) and/or non-hematologic events at a 12-month follow-up evaluation. Dasatinib was a safe and effective treatment for Japanese patients with imatinib-resistant or imatinib-intolerant CML. In addition, the molecular response at 1 or 3 months predicted a response to dasatinib at 12 or 18 months.

BCR-ABL tyrosine kinase inhibitors (TKI) have dramatically improved therapy for chronic myelogenous leukemia (CML). However, several problems leading to TKI resistance still impede a complete cure of this disease. IFN regulatory factor-8 (IRF8) is a transcription factor essential for the development and functions of immune cells, including dendritic cells. Irf8(-/-) mice develop a CML-like disease and IRF8 expression is downregulated in patients with CML, suggesting that IRF8 is involved in the pathogenesis of CML. In this study, by using a murine CML model, we show that BCR-ABL strongly inhibits a generation of dendritic cells from an early stage of their differentiation in vivo, concomitant with suppression of Irf8 expression. Forced expression of IRF8 overrode BCR-ABL (both wild-type and T315I-mutated) to rescue dendritic cell development in vitro, indicating that the suppression of Irf8 causes dendritic cell deficiency. Gene expression profiling revealed that IRF8 restored the expression of a significant portion of BCR-ABL-dysregulated genes and predicted that BCR-ABL has immune-stimulatory potential. Indeed, IRF8-rescued BCR-ABL-expressing dendritic cells were capable of inducing CTLs more efficiently than control dendritic cells. Altogether, our findings suggest that IRF8 is an attractive target in next-generation therapies for CML., (©2013 AACR)

A prospective multicenter Phase II study was performed to examine the efficacy and safety of imatinib therapy in newly diagnosed Japanese patients with chronic-phase CML. Patients were scheduled to receive imatinib 400 mg daily. Plasma imatinib concentrations were measured by liquid chromatography-tandem mass spectrometry. In 481 evaluable patients, estimated 7-year overall survival (OS) and event-free survival (EFS) at a median follow-up of 65 months were 93% and 87%, respectively. Because imatinib dosage was reduced in many patients due mainly to adverse events, subgroup analysis was performed according to the mean daily dose during the first 24 months of treatment: ≥360 mg (400-mg group; n = 294), 270-359 mg (300-mg group; n = 90) and <270 mg (200-mg group; n = 67). There were no significant differences in OS and EFS between the 300- and 400-mg groups; however, cumulative rates of complete cytogenetic and major molecular responses differed significantly between the two groups. There were no significant differences in mean imatinib trough levels between these two groups for the patients in whom trough levels had been measured. Survival and efficacy in the 200-mg group were markedly inferior to the former two groups. These results suggest that, although a daily dose of 400 mg imatinib is associated with better outcomes, 300 mg imatinib may be adequate for a considerable number of Japanese patients who are intolerant to 400 mg imatinib. Blood level monitoring would be useful to determine the optimal dose of imatinib., (© 2012 Japanese Cancer Association.)

Chronic myelogenous leukemia (CML) is characterized by a reciprocal chromosomal translocation (9;22) that generates the Bcr-Abl fusion gene. BCR-ABL transforming activity is mediated by critical downstream signaling pathways that are aberrantly activated by tyrosine kinases. However, the mechanisms of BCR-ABL anti-apoptotic effects and the signaling pathways by which BCR-ABL influences apoptosis in BCR-ABL-expressing cells are poorly defined. In this study, we found that treatment with ABL kinase inhibitors or depletion of BCR-ABL induced the expression of RAB45 messenger RNA and protein and induced apoptosis via reduction of mitochondrial membrane potential and p38 activation in CML cell lines and BCR-ABL(+) progenitor cells from CML patients. Overexpressed RAB45 induced the activation of caspases-3 and -9 and reduced the expression of Survivin, XIAP, c-IAP1 and c-IAP2 in CML cells. Moreover, in colony-forming cells derived from CML-aldehyde dehydrogenase(hi)/CD34(+) cells, treatment with ABL kinase inhibitors induced RAB45 expression and reduced mitochondrial membrane potential, resulting in inhibited colony formation of Bcr-Abl(+) progenitor cells. The overexpression of RAB45 significantly decreased colony numbers and induced apoptosis through the activation of caspases-3 and -9. Furthermore, the overexpression of RAB45 increased the phosphorylation levels of p38, resulting in the induction of apoptosis and inhibition of proliferation of CML progenitor cells. Our results identify a new signaling molecule involved in BCR-ABL modulation of apoptosis and suggest that RAB45 induction strategies may have therapeutic utility in patients with CML.

The aim of this retrospective study was to evaluate the toxicity profiles of dasatinib in patients with Philadelphia chromosome positive chronic myeloid leukemia (CML) or acute lymphatic leukemia (ALL) who were intolerant to imatinib, and who had been enrolled in our previous clinical trials to evaluate efficacy of dasatinib in patients resistant or tolerant to imatinib therapy. Twenty-four patients with CML and four with ALL were enrolled in the clinical studies to evaluate the efficacy according to the eligibility criteria related to intolerance to imatinib therapy. The toxicities reported during imatinib therapy were non-hematological toxicities in 23 patients and hematological toxicities in six patients. Patients were administered dasatinib 50-70 mg BID or 100 mg QD. Cross intolerance was observed in four patients who showed hematological toxicity after dasatinib treatment. However, it was possible to successfully continue therapy with only temporary interruption. No cross intolerance in non-hematological toxicity was found with the exception of one patient who showed cross intolerance, which did not result in treatment interruption. Dasatinib can be safely administered to imatinib-intolerant CML or Ph-positive ALL patients.

Chronic myelogenous leukemia (CML) is characterized by a reciprocal chromosomal translocation (9;22) that generates the Bcr-Abl fusion gene. The Ras/Raf-1/MEK/ERK pathway is constitutively activated in Bcr-Abl-transformed cells, and Ras activity enhances the oncogenic ability of Bcr-Abl. However, the mechanism by which Bcr-Abl activates the Ras pathway is not completely understood. Raf kinase inhibitor protein (RKIP) inhibits activation of MEK by Raf-1 and its downstream signal transduction, resulting in blocking the MAP kinase pathway. In the present study, we found that RKIP was depleted in CML cells. We investigated the interaction between RKIP and Bcr-Abl in CML cell lines and Bcr-Abl(+) progenitor cells from CML patients. The Abl kinase inhibitors and depletion of Bcr-Abl induced the expression of RKIP and reduced the pERK1/2 status, resulting in inhibited proliferation of CML cells. Moreover, RKIP up-regulated cell cycle regulator FoxM1 expression, resulting in G(1) arrest via p27(Kip1) and p21(Cip1) accumulation. In colony-forming unit granulocyte, erythroid, macrophage, megakaryocyte, colony-forming unit-granulocyte macrophage, and burst-forming unit erythroid, treatment with the Abl kinase inhibitors and depletion of Bcr-Abl induced RKIP and reduced FoxM1 expressions, and inhibited colony formation of Bcr-Abl(+) progenitor cells, whereas depletion of RKIP weakened the inhibition of colony formation activity by the Abl kinase inhibitors in Bcr-Abl(+) progenitor cells. Thus, Bcr-Abl represses the expression of RKIP, continuously activates pERK1/2, and suppresses FoxM1 expression, resulting in proliferation of CML cells.

The constitutive activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway commonly occurs in cancers and is a crucial event in tumorigenesis. Chronic myelogenous leukemia (CML) is characterized by a reciprocal chromosomal translocation (9;22) that generates the Bcr-Abl fusion gene. The PI3K/Akt pathway is activated by Bcr-Abl chimera protein and mediates the leukemogenesis in CML. However, the mechanism by which Bcr-Abl activates the PI3K/Akt pathway is not completely understood. In the present study, we found that pleckstrin homology domain leucine-rich repeat protein phosphatases 1 and 2 (PHLPP1 and PHLPP2) were depleted in CML cells. We investigated the interaction between PHLPPs and Bcr-Abl in CML cell lines and Bcr-Abl+ progenitor cells from CML patients. The Abl kinase inhibitors and depletion of Bcr-Abl induced the expression of PHLPP1 and PHLPP2, which dephosphorylated Ser-473 on Akt1, -2, and -3, resulting in inhibited proliferation of CML cells. The reduction of PHLPP1 and PHLPP2 expression by short interfering RNA in CML cells weakened the Abl kinase inhibitor-mediated inhibition of proliferation. In colony-forming unit-granulocyte, erythroid, macrophage, megakaryocyte; colony-forming unit-granulocyte, macrophage; and burst-forming unit-erythroid, treatment with the Abl kinase inhibitors and depletion of Bcr-Abl induced PHLPP1 and PHLPP2 expression and inhibited colony formation of Bcr-Abl+ progenitor cells, whereas depletion of PHLPP1 and PHLPP2 weakened the inhibition of colony formation activity by the Abl kinase inhibitors in Bcr-Abl+ progenitor cells. Thus, Bcr-Abl represses the expression of PHLPP1 and PHLPP2 and continuously activates Akt1, -2, and -3 via phosphorylation on Ser-473, resulting in the proliferation of CML cells.

We report a patient with chronic myelogenous leukemia that responded to imatinib mesilate after relapse of blastic crisis following allogeneic bone marrow transplantation. The patient received an unrelated bone marrow transplantation in the 3rd chronic phase, after which the 3rd blastic crisis occurred 5 months later. Since the case was refractory to chemotherapy at that time, imatinib mesilate (600 mg/day) was given, which resulted in a complete cytogenetical remission (CCR). The CCR has maintained for 11 months.

We describe a case of a 49-year-old man with chronic myelogenous leukemia (CML) whose coincidental psoriasis resolved following allogeneic bone marrow transplantation (BMT). The patient had suffered from psoriasis for 20 years and was treated with corticosteroid ointment. He was diagnosed as having CML in 1998, and his psoriasis deteriorated following interferon therapy. In March 1999, he received a BMT from an HLA-identical sister after undergoing a conditioning regimen involving busulfan, cytosine arabinoside, and cyclophosphamide. Prophylaxis of acute graft-versus-host disease was done using short-term methotrexate and cyclosporin A. His psoriasis improved immediately and disappeared completely on day 70 after BMT. For 2.5 years, his CML remains in remission and he is free of psoriasis without undergoing immunosuppressive therapy. This case suggests the potential benefits of the treatment of immune-mediated diseases with allogeneic BMT., (Copyright 2002 Wiley-Liss, Inc.)

We report a patient with chronic myelogenous leukemia who received a second transplant from a one-locus HLA-mismatched unrelated donor after rejection of an initial bone marrow graft. For the first transplant, HLAs were fully matched, conditioning with busulfan + cyclophosphamide (CY) was applied, and cyclosporin A + short-term methotrexate (sMTX) was used for prophylaxis against GVHD. A complete chimera was not obtained, and the graft was rejected on day 122. For the second transplant, there was a one-HLA locus (DR) mismatch, conditioning was done with total body irradiation + cytarabine + CY, and GVHD prophylaxis consisted of FK506 + sMTX. Engraftment was obtained on day 27, and no graft failure was occurred at the time of writing. This case suggests that strong immunosuppression may have prevented rejection of the second bone marrow graft.

A 35-year-old man with chronic myeloid leukemia (CML) in blastic crisis (BC) received an allogeneic bone marrow transplant from an unrelated donor in October 1998 after three cycles of chemotherapy. BC relapse developed on day 349 after transplantation. After one cycle of chemotherapy and treatment with interferon, the patient received donor lymphocyte infusion (DLI), and this resulted in a complete cytogenetic response 21 days later. Grade III acute graft-versus-host disease developed on day 25 after DLI, but this was resolved after administration of prednisolone. Disease relapse occurred at extramedullary sites on day 162 after DLI, and the patient died of sepsis after receiving chemotherapy. This case illustrates that unrelated DLI can induce remission successfully in patients with relapse of CML in BC through a graft-versus-leukemia effect.

In a 27-year-old female with Turner syndrome mosaic, Philadelphia (Ph) chromosome-positive chronic myeloid leukemia (CML) occurred only in the monosomic cells (45, Xc). Extensive cytogenetic studies, including triple-color fluorescence in situ hybridization (FISH), revealed that Ph-positive monosomic cells (45, Xc), Ph-negative monosomic cells and normal diploid cells (46, XX) were present in her bone marrow at diagnosis. After successful interferon therapy, the non-leukemia cells expanded and reconstituted normal hematopoiesis resulting in complete cytogenetic response, following the selective suppression of the monosomic Ph-positive leukemia clone. The ratio of Xc to XX cells in bone marrow cells was significantly increased to that in skin fibroblasts. Moreover, the ratio of Ph-positive cells to Ph-negative cells was found to be significantly different between karyotyping and FISH. Studies of this quite unique case not only confirmed the clonality of CML, effectiveness of interferon-alpha and X chromosome imbalance among different tissues, but also demonstrated a discrepant increase of the BCR/ABL-positive clone in CML. The latter supports the hypothesis that reduced programmed cell death may be the primary mechanism responsible for the expansion of the leukemia clone in CML. Our study verifies the importance of extensive analysis of a neoplastic disease in patients with a constitutional chromosomal abnormality.

A 48-year-old woman was admitted with chronic myelogenous leukemia in November, 1996 and was treated with hydroxyurea (HU), because of marked leukocytosis; WBC 404,000/microliter. On January 29, 1997, administration of HU was stopped, and treatment of alpha-interferon (IFN alpha) was started with 6x 10(6)U, every day. However, the WBC count rose from 19,600/microliter to 56,800/microliter, and the combination of IFN and 2,000 mg of HU was started on February 4. The dose of HU was reduced to 500 mg on February 27, and the IFN administration was reduced to 3 times a week from April 4, because the WBC count was less than 10,000/microliter. Pancytopenia was revealed in May. The bone marrow biopsy specimen demonstrated marked hypoplastic changes, and chromosome analysis of bone marrow cells showed Philadelphia chromosome in all 20 metaphases. Treatment was interrupted for 7 months, but hematologic parameters did not recover. There were 9 cases reported in detail with bone marrow hypoplasia induced by IFN. One patient received IFN alone and 8 patients received anti-cancer drugs before treatment of IFN. We concluded that great care must be taken for IFN treatment of CML.