Phase 2 studies of lenalidomide, subcutaneous bortezomib, and dexamethasone as induction therapy in patients with newly diagnosed multiple myeloma.

There are limited prospective data on lenalidomide, subcutaneous bortezomib, and dexamethasone (RsqVd) in transplant-eligible/transplant-ineligible patients with newly diagnosed multiple myeloma. Reliable biomarkers for efficacy and toxicity are required to better tailor therapy. Two parallel studies were conducted by Cancer Trials Ireland (CTI; NCT02219178) and the Dana-Farber Cancer Institute (DFCI; NCT02441686). Patients received four 21-day cycles of RsqVd and could then receive either another 4 cycles of RsqVd or undergo autologous stem cell transplant. Postinduction/posttransplant, patients received lenalidomide maintenance, with bortezomib included for high-risk patients. The primary endpoint was overall response rate (ORR) after 4 cycles of RsqVd. Eighty-eight patients were enrolled and 84 treated across the two studies; median age was 64.7 (CTI study) and 60.0 years (DFCI study), and 59% and 57% had stage II-III disease. Pooled ORR after 4 cycles in evaluable patients was 93.5%, including 48.1% complete or very good partial responses (CTI study: 91.9%, 59.5%; DFCI study: 95.0%, 37.5%), and in the all-treated population was 85.7% (44.0%). Patients received a median of 4 (CTI study) and 8 (DFCI study) RsqVd cycles; 60% and 31% of patients (CTI study) and 33% and 51% of patients (DFCI study) underwent transplant or received further RsqVd induction, respectively. The most common toxicity was peripheral neuropathy (pooled: 68%, 7% grade 3-4; CTI study: 57%, 7%; DFCI study: 79%, 7%). Proteomics analyses indicated elevated kallikrein-6 in good versus poor responders, decreased midkine in good responders, and elevated macrophage inflammatory protein 1-alpha in patients who stopped treatment from neurotoxicity, suggesting predictive biomarkers warranting further investigation.

Co-Formulation of Amphiphilic Cationic and Anionic Cyclodextrins Forming Nanoparticles for siRNA Delivery in the Treatment of Acute Myeloid Leukaemia.

Non-viral delivery of therapeutic nucleic acids (NA), including siRNA, has potential in the treatment of diseases with high unmet clinical needs such as acute myeloid leukaemia (AML). While cationic biomaterials are frequently used to complex the nucleic acids into nanoparticles, attenuation of charge density is desirable to decrease in vivo toxicity. Here, an anionic amphiphilic CD was synthesised and the structure was confirmed by Fourier-transform infrared spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR), and high-resolution mass spectrometry (HRMS). A cationic amphiphilic cyclodextrin (CD) was initially used to complex the siRNA and then co-formulated with the anionic amphiphilic CD. Characterisation of the co-formulated NPs indicated a significant reduction in charge from 34 ± 7 mV to 24 ± 6 mV (p < 0.05) and polydispersity index 0.46 ± 0.1 to 0.16 ± 0.04 (p < 0.05), compared to the cationic CD NPs. Size was similar, 161−164 nm, for both formulations. FACS and confocal microscopy, using AML cells (HL-60), indicated a similar level of cellular uptake (60% after 6 h) followed by endosomal escape. The nano co-formulation significantly reduced the charge while maintaining gene silencing (21%). Results indicate that blending of anionic and cationic amphiphilic CDs can produce bespoke NPs with optimised physicochemical properties and potential for enhanced in vivo performance in cancer treatment.

Platelet hyperactivation in multiple myeloma is also evident in patients with premalignant monoclonal gammopathy of undetermined significance.

Thrombotic events are common in patients with multiple myeloma (MM), smouldering myeloma (SM) and monoclonal gammopathy of undetermined significance (MGUS). Previous studies have indicated platelet hyperactivation as a feature of thrombotic risk in MM, but there is a dearth of data in MGUS. In the present study, multiparameter analysis of platelet activation and responsiveness was investigated by flow cytometry in patients with MGUS, SM/MM and healthy controls (HCs). The median platelet surface CD63 levels, annexin V and PAC-1 antibody (specific for activated integrin αIIbß3) binding were significantly elevated in patients with MGUS versus the HCs. These markers were also elevated in SM/MM, but not significantly. In all, 74% of MGUS and 38% of SM/MM patients had one or more elevated marker of platelet activation, compared to 19% of the HCs. Marker-specific hyporesponsiveness of platelets to agonist [adenosine diphosphate (ADP), thrombin receptor-activating peptide 6] stimulation in vitro was observed, with significantly reduced surface levels of P-selectin in response to ADP in patients with MGUS. Platelet-leucocyte aggregates were not altered in patients, while platelet-associated immunoglobulins were elevated in a subset of patients. Overall, we found that platelet hyperactivation is prevalent in both MGUS and SM/MM patients and is potentially related to hyporesponsiveness. These observations suggest that further investigation of the predictive and prognostic value of platelet hyperactivation in such patients is warranted.

Validation of phlebotomy performance metrics developed as part of a proficiency-based progression initiative to mitigate wrong blood in tube.

AIMS: The purpose of this study was to (1) characterise the procedure of phlebotomy, deconstruct it into its constituent parts and develop a performance metric for the purpose of training healthcare professionals in a large teaching hospital and to (2) evaluate the construct validity of the phlebotomy metric and establish a proficiency benchmark. METHOD: By engaging with a multidisciplinary team with a wide range of experience of preanalytical errors in phlebotomy and observing video recordings of the procedure performed in the actual working environment, we defined a performance metric. This was brought to a modified Delphi meeting, where consensus was reached by an expert panel. To demonstrate construct validity, we used the metric to objectively assess the performance of novices and expert practitioners. RESULTS: A phlebotomy metric consisting of 11 phases and 77 steps was developed. The mean inter-rater reliability was 0.91 (min 0.83, max 0.95). The expert group completed more steps of the procedure (72 vs 69), made fewer errors (19 vs 13, p=0.014) and fewer critical errors (1 Vs 4, p=0.002) than the novice group. CONCLUSIONS: The metrics demonstrated construct validity and the proficiency benchmark was established with a minimum observation of 69 steps, with no critical errors and no more than 13 errors in total.

The Importance of Alpha-Actinin Proteins in Platelet Formation and Function, and Their Causative Role in Congenital Macrothrombocytopenia.

The actin cytoskeleton plays a central role in platelet formation and function. Alpha-actinins (actinins) are actin filament crosslinking proteins that are prominently expressed in platelets and have been studied in relation to their role in platelet activation since the 1970s. However, within the past decade, several groups have described mutations in ACTN1/actinin-1 that cause congenital macrothrombocytopenia (CMTP)-accounting for approximately 5% of all cases of this condition. These findings are suggestive of potentially novel functions for actinins in platelet formation from megakaryocytes in the bone marrow and/or platelet maturation in circulation. Here, we review some recent insights into the well-known functions of actinins in platelet activation before considering possible roles for actinins in platelet formation that could explain their association with CMTP. We describe what is known about the consequences of CMTP-linked mutations on actinin-1 function at a molecular and cellular level and speculate how these changes might lead to the alterations in platelet count and morphology observed in CMTP patients. Finally, we outline some unanswered questions in this area and how they might be addressed in future studies.

All-trans retinoic acid (ATRA)-induced TFEB expression is required for myeloid differentiation in acute promyelocytic leukemia (APL).

OBJECTIVE: In acute promyelocytic leukemia (APL), normal retinoid signaling is disrupted by an abnormal PML-RARα fusion oncoprotein, leading to a block in cell differentiation. Therapeutic concentrations of all-trans-retinoic acid (ATRA) can restore retinoid-induced transcription and promote degradation of the PML-RARα protein. Autophagy is a catabolic pathway that utilizes lysosomal machinery to degrade intracellular material and facilitate cellular re-modeling. Recent studies have identified autophagy as an integral component of ATRA-induced myeloid differentiation. METHODS: As the molecular communication between retinoid signaling and the autophagy pathway is not defined, we performed RNA sequencing of NB4 APL cells treated with ATRA and examined autophagy-related transcripts. RESULTS: ATRA altered the expression of >80 known autophagy-related transcripts, including the key transcriptional regulator of autophagy and lysosomal biogenesis, TFEB (11.5-fold increase). Induction of TFEB and its transcriptional target, sequestosome 1 (SQSTM1, p62), is reduced in ATRA-resistant NB4R cells compared to NB4 cells. TFEB knockdown in NB4 cells alters the expression of transcriptional targets of TFEB and reduces CD11b transcript levels in response to ATRA. CONCLUSIONS: We show for the first time that TFEB plays an important role in ATRA-induced autophagy during myeloid differentiation and that autophagy induction potentiates leukemic cell differentiation (Note: this study includes data obtained from NCT00195156, https://clinicaltrials.gov/show/NCT00195156).

Physician and practice characteristics associated with immunoglobulin test ordering.

Background: Primary care test requests for serum immunoglobulins are rising rapidly, with concerns that many requests may be unnecessary. Evidence suggests some characteristics of general practitioners (GPs) and practices are associated with higher test ordering. Objective: To identify the physician and practice characteristics associated with immunoglobulin test ordering. Methods: Retrospective, cross-sectional study using routine laboratory data on primary care serum immunoglobulin requests. Data were linked with GP patient list size data. The primary outcome measure was the count of test requests per GP. Predictor variables were physician gender, years experience, practice region and type (number of GPs), GP patient list size and composition. Mixed-effects multilevel regression models were used to calculate incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for the associations between physician and practice characteristics and GP requesting. Sensitivity analysis was performed by limiting the model to the more than 70 years age category. Results: In total, 5990 immunoglobulin tests were ordered by 481 GPs in the South of Ireland during 2013. The number of tests ordered by individual GPs varied from one to 377. In the final fully adjusted Poisson regression analysis, female gender (IRR: 1.81; 95% CI: 1.45-2.26) and less experience (IRR: 2.27; 95% CI: 1.47-3.51) were associated with higher requesting (P < 0.001). None of the practice factors were associated with test ordering. Sensitivity analysis on the 70 years or more age category found similar results. Conclusion: Further research is required to explore the potential reasons for higher requesting among GPs with fewer years of experience and also among female GPs.

Antibody-Targeted Cyclodextrin-Based Nanoparticles for siRNA Delivery in the Treatment of Acute Myeloid Leukemia: Physicochemical Characteristics, in Vitro Mechanistic Studies, and ex Vivo Patient Derived Therapeutic Efficacy.

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults and is associated with high relapse rates. It is known that leukemia stem cells (LSCs), a very small subpopulation of the total number of leukemic cells, maintain the leukemia phenotype (∼80-90% of AML remain the same as at first diagnosis), display chemotherapy resistance, and contribute to disease regeneration. Therefore, targeting LSCs could control the relapse of AML. Small interfering RNA (siRNA), an effector of the RNA interference (RNAi) pathway, can selectively downregulate any gene implicated in the pathology of disease, presenting great potential for treatment of AML. In this study an antibody targeted cyclodextrin-based nanoparticle (NP) (CD.DSPE-PEG-Fab) was developed for siRNA delivery specifically to AML LSCs. The targeted CD.siRNA.DSPE-PEG-Fab formulation, where Fab specifically targets the IL-3 receptor α-chain (IL-3Rα, also known as CD123, a cell surface antigen for human AML LSCs), achieved antigen-mediated cellular uptake in KG1 cells (an AML leukemia stem and progenitor cell line). Efficient delivery of bromodomain-containing protein 4 (BRD4) siRNA using the targeted formulation resulted in downregulation of the corresponding mRNA and protein in KG1 cells and in ex vivo primary AML patient derived samples. The resulting silencing of BRD4 induced myeloid differentiation and triggered leukemia apoptosis. In addition, a synergistic therapeutic effect was detected when administered in combination with the chemotherapeutic, cytarabine (Ara-C). These results indicate the clinical potential of the antibody-tagged cyclodextrin NP for targeted delivery of therapeutic siRNA in the treatment of AML.

A novel 33-Gene targeted resequencing panel provides accurate, clinical-grade diagnosis and improves patient management for rare inherited anaemias.

Accurate diagnosis of rare inherited anaemias is challenging, requiring a series of complex and expensive laboratory tests. Targeted next-generation-sequencing (NGS) has been used to investigate these disorders, but the selection of genes on individual panels has been narrow and the validation strategies used have fallen short of the standards required for clinical use. Clinical-grade validation of negative results requires the test to distinguish between lack of adequate sequencing reads at the locations of known mutations and a real absence of mutations. To achieve a clinically-reliable diagnostic test and minimize false-negative results we developed an open-source tool (CoverMi) to accurately determine base-coverage and the 'discoverability' of known mutations for every sample. We validated our 33-gene panel using Sanger sequencing and microarray. Our panel demonstrated 100% specificity and 99·7% sensitivity. We then analysed 57 clinical samples: molecular diagnoses were made in 22/57 (38·6%), corresponding to 32 mutations of which 16 were new. In all cases, accurate molecular diagnosis had a positive impact on clinical management. Using a validated NGS-based platform for routine molecular diagnosis of previously undiagnosed congenital anaemias is feasible in a clinical diagnostic setting, improves precise diagnosis and enhances management and counselling of the patient and their family.

Regulation of Trib2 by an E2F1-C/EBPα feedback loop in AML cell proliferation.

The loss of regulation of cell proliferation is a key event in leukemic transformation, and the oncogene tribbles (Trib)2 is emerging as a pivotal target of transcription factors in acute leukemias. Deregulation of the transcription factor E2F1, normally repressed by CCAAT enhancer-binding protein α (C/EBPα)-p42, occurs in acute myeloid leukemia (AML), resulting in the perturbation of cell cycle and apoptosis, emphasizing its importance in the molecular pathogenesis of AML. Here we show that E2F family members directly regulate Trib2 in leukemic cells and identify a feedback regulatory loop for E2F1, C/EBPα, and Trib2 in AML cell proliferation and survival. Further analyses revealed that E2F1-mediated Trib2 expression was repressed by C/EBPα-p42, and in normal granulocyte/macrophage progenitor cells, we detect C/EBPα bound to the Trib2 promoter. Pharmacological inhibition of the cell cycle or Trib2 knockdown resulted in a block in AML cell proliferation. Our work proposes a novel paradigm whereby E2F1 plays a key role in the regulation of Trib2 expression important for AML cell proliferation control. Importantly, we identify the contribution of dysregulated C/EBPα and E2F1 to elevated Trib2 expression and leukemic cell survival, which likely contributes to the initiation and maintenance of AML and may have significant implications for normal and malignant hematopoiesis.

Retinoid receptor signaling and autophagy in acute promyelocytic leukemia.

Retinoids are a family of signaling molecules derived from vitamin A with well established roles in cellular differentiation. Physiologically active retinoids mediate transcriptional effects on cells through interactions with retinoic acid (RARs) and retinoid-X (RXR) receptors. Chromosomal translocations involving the RARα gene, which lead to impaired retinoid signaling, are implicated in acute promyelocytic leukemia (APL). All-trans-retinoic acid (ATRA), alone and in combination with arsenic trioxide (ATO), restores differentiation in APL cells and promotes degradation of the abnormal oncogenic fusion protein through several proteolytic mechanisms. RARα fusion-protein elimination is emerging as critical to obtaining sustained remission and long-term cure in APL. Autophagy is a degradative cellular pathway involved in protein turnover. Both ATRA and ATO also induce autophagy in APL cells. Enhancing autophagy may therefore be of therapeutic benefit in resistant APL and could broaden the application of differentiation therapy to other cancers. Here we discuss retinoid signaling in hematopoiesis, leukemogenesis, and APL treatment. We highlight autophagy as a potential important regulator in anti-leukemic strategies.

Challenges of providing biochemistry results in a patient with Evans syndrome.

A case report of in vivo hemolysis in a female patient with Evans syndrome is described. The patient was admitted with anemia and jaundice and, during her 26-day hospital admission, had 83 samples taken for biochemistry analyses. The laboratory hemolytic index (HI) was frequently elevated due to persistent complement-mediated in vivo hemolysis despite multiple lines of therapy. Initially, the release of many biochemical parameters was blocked per the manufacturer´s recommendations and reported as "sample hemolyzed". The patient developed severe acute kidney injury, ultimately requiring dialysis. Automated and timely reporting of indicative creatinine and other biochemical results in the context of ongoing hemolysis, therefore, became essential to patient care. Following a review of literature from various sources, a laboratory algorithm was designed to ensure the timely release of numerical biochemical values, where possible, with appropriate interpretative comments appended. Biochemistry, hematology, and nephrology teams were in regular communication to ensure patient samples were rapidly identified, analyzed and validated according to the algorithm, informing timely, safe and appropriate patient care. Ultimately, the patient died due to multiple disease- and treatment-related complications. In conjunction with clinical users, laboratories should plan for situations, such as in vivo hemolysis, where significant unavoidable interferences in biochemistry methodologies may occur in an ongoing manner for certain patients. Reporting categorical or best-estimate biochemistry results in such cases can be safer for patients than failing to report any results. Interpretation of these results by clinical teams requires input from appropriately trained and qualified laboratory personnel.

An evaluation of the utilisation of biosimilar monoclonal antibody drugs in Ireland and barriers to their usage.

BACKGROUND: While biologic drugs have demonstrated efficacy across a range of indications, patient access to these drugs is constrained due to their high cost. Biosimilars provide a means to increase patient access while reducing the financial burden. AIMS: The primary objective was to determine the current usage of biosimilar and reference trastuzumab and rituximab in four Irish hospitals. A secondary objective involved determining barriers to biosimilar usage. METHODS: This project involved a retrospective chart review to analyse the usage of reference and biosimilar versions of trastuzumab and rituximab. Additionally, a prospective cross-sectional study identified barriers to the usage of biosimilars via the distribution of a novel questionnaire to patients, pharmacists, doctors and students. RESULTS: The utilisation of biosimilar intravenous trastuzumab and rituximab ranged from 39 to 100%, and 0 to 89%, respectively. A total of n = 479 questionnaire responses were included. Biosimilar awareness was significantly lower among 'Doctors and Medical Students' (45.3%; 95% [CI, 33.8-57.3%]) compared to 'Pharmacists and Pharmacy Students' (97.1%; 95% [CI, 94-98.8%; comparison p < 0.001]). A significant majority of healthcare professionals agreed biosimilars should have consistent nomenclature (p < 0.001). A significant majority of patients (87.3%, 95% [CI, 81.3-92%; p < 0.001]) indicated that they would agree to commence using a biosimilar medicine. CONCLUSION: Biosimilar versions of trastuzumab and rituximab were in use to a variable extent. There remains a considerable opportunity to further increase the usage to maximise their potential benefits. A series of challenges were identified including reduced awareness among the medical profession and lack of clear nomenclature.

Dealing with digital paralysis: Surviving a cyberattack in a National Cancer center.

INTRODUCTION: Cyberattacks represent a growing threat for healthcare delivery globally. We assess the impact and implications of a cyberattack on a cancer center in Ireland. METHODS: On May 14th 2021 (day 0) Cork University Hospital (CUH) Cancer Center was involved in the first national healthcare ransomware attack in Ireland. Contingency plans were only present in laboratory services who had previously experienced information technology (IT) failures. No hospital cyberattack emergency plan was in place. Departmental logs of activity for 120 days after the attack were reviewed and compared with historical activity records. Daily sample deficits (routine daily number of samples analyzed - number of samples analyzed during cyberattack) were calculated. Categorical variables are reported as median and range. Qualitative data were collected via reflective essays and interviews with key stakeholders from affected departments in CUH. RESULTS: On day 0, all IT systems were shut down. Radiotherapy (RT) treatment and cancer surgeries stopped, outpatient activity fell by 50%. hematology, biochemistry and radiology capacity fell by 90% (daily sample deficit (DSD) 2700 samples), 75% (DSD 2250 samples), and 90% (100% mammography/PET scan) respectively. Histopathology reporting times doubled (7 to 15 days). Radiotherapy (RT) was interrupted for 113 patients in CUH. The median treatment gap duration was six days for category 1 patients and 10 for the remaining patients. Partner organizations paused all IT links with CUH. Outsourcing of radiology and radiotherapy commenced, alternative communication networks and national conference calls in RT and Clinical Trials were established. By day 28 Email communication was restored. By day 210 reporting and data storage backlogs were cleared and over 2000 computers were checked/replaced. CONCLUSION: Cyberattacks have rapid, profound and protracted impacts. While laboratory and diagnostic deficits were readily quantified, the impact of disrupted/delayed care on patient outcomes is less readily quantifiable. Cyberawareness and cyberattack plans need to be embedded in healthcare. POLICY SUMMARY: Cyberattacks pose significant challenges for healthcare systems, impacting patient care, clinical outcomes, and staff wellbeing. This study provides a comprehensive review of the impact of the Conti ransomware attack on cancer services in Cork University Hospital (CUH), the first cyberattack on a national health service. Our study highlights the widespread disruption caused by a cyberattack including shutdown of information technology (IT) services, marked reduction in outpatient activity, temporary cessation of essential services such as radiation therapy. We provide a framework for other institutions for mitigating the impact of a cyberattack, underscoring the need for a cyberpreparedness plan similar to those made for natural disasters and the profound legacy of a cyberattack on patient care.

The impact of expanded access programs for systemic anticancer therapy in an Irish cancer centre.

BACKGROUND: Expanded access programs (EAPs) allow cancer patients with unmet clinical need to obtain access to pre-authorisation treatments. There is no standardised process for implementing these programs nationally, and real-world data on their impact is lacking. AIMS: This study aimed to evaluate the prevalence of such EAPs and their impact in a cancer centre. METHODS: Data relating to adult cancer patients treated via EAPs from 2011 to 2021 in three Cork university hospitals was collated. Descriptive statistics were employed to get an overview of the impact these programs currently have on cancer care provision. RESULTS: We identified 193 patients who accessed EAPs during the study period, availing of 33 separate drugs for a total of 50 different cancer indications. The prevalence of EAP usage was shown to have been trending upwards in recent years with a total of 189 programs being accessed throughout the period. Drugs provided were from a number of different anti-cancer drug classes, particularly targeted therapies (n = 18) and immune checkpoint inhibitors (n = 17). Cancers from a wide range of both solid and liquid tumour types were treated with EAP drugs, and patients treated were from across a broad spectrum of ages (26-82, SD 11.99). CONCLUSIONS: EAPs have an increasing role in accessing novel cancer therapies in our community and by extension nationally. Equity of EAP access would be facilitated by a national registry of available agents which we have established. Assessment of their benefits and toxicities would be enhanced by the requirement for a real-world database as a condition of EAP approval.

A multi-centre retrospective study of rituximab use in the treatment of relapsed or resistant warm autoimmune haemolytic anaemia.

This retrospective analysis assessed the response, safety and duration of response to standard dose rituximab 375 mg/m(2) weekly for four weeks as therapy for patients with primary or secondary warm autoimmune haemolytic anaemia (WAIHA), who had failed initial treatment. Thirty-four patients received rituximab for WAIHA in seven centres in the Republic of Ireland. The overall response rate was 70·6% (24/34) with 26·5% (9/34) achieving a complete response (CR). The time to response was 1 month post-initiation of rituximab in 87·5% (21/24) and 3 months in 12·5% (3/24) of patients. The median duration of follow-up was 36 months (range 6-90 months). Of the patients who responded, 50% (12/24) relapsed during follow up with a median time to next treatment of 16·5 months (range 6-60 months). Three patients were re-treated with rituximab 375 mg/m2 weekly for four weeks at relapse and responded. There was a single episode of neutropenic sepsis. Rituximab is an effective and safe treatment for WAIHA but a significant number of patients will relapse in the first two years post treatment. Re-treatment was effective in a small number of patients, suggesting that intermittent pulse treatment or maintenance treatment may improve long-term response.

Induction of autophagy by Imatinib sequesters Bcr-Abl in autophagosomes and down-regulates Bcr-Abl protein.

Chronic Myeloid Leukemia (CML) is a disease of hematopoietic stem cells which harbor the chimeric gene Bcr-Abl. Expression levels of this constitutively active tyrosine kinase are critical for response to tyrosine kinase inhibitor treatment and also disease progression, yet the regulation of protein stability is poorly understood. We have previously demonstrated that imatinib can induce autophagy in Bcr-Abl expressing cells. Autophagy has been associated with the clearance of large macromolecular signaling complexes and abnormal proteins, however, the contribution of autophagy to the turnover of Bcr-Abl protein in imatinib treated cells is unknown. In this study, we show that following imatinib treatment, Bcr-Abl is sequestered into vesicular structures that co-localize with the autophagy marker LC3 or GABARAP. This association is inhibited by siRNA mediated knockdown of autophagy regulators (Beclin 1/ATG7). Pharmacological inhibition of autophagy also reduced Bcr-Abl/LC3 co-localization in both K562 and CML patient cells. Bcr-Abl protein expression was reduced with imatinib treatment. Inhibition of both autophagy and proteasome activity in imatinib treated cells was required to restore Bcr-Abl protein levels to those of untreated cells. This ability to down-regulate Bcr-Abl protein levels through the induction of autophagy may be an additional and important feature of the activity of imatinib.