Incidence of bleeding events in patients on concomitant tyrosine kinase inhibitors and selective serotonin reuptake inhibitors

INTRODUCTION

In this study, we aim to determine the risk of bleeding or thrombosis with concurrent use of tyrosine kinase inhibitors (TKIs) used to treat CML, and serotonin reuptake inhibitors (SSRIs).

METHODS

We conducted a retrospective cohort study of patients with CP-CML cared for at Massachusetts General Hospital (MGH) between April 2016 to February 2021. Participants were included if diagnosed with CP-CML and began TKI treatment (imatinib, dasatinib, nilotinib, bosutinib, or ponatinib) after April 2016.

RESULTS

One hundred patients were evaluated, eighty of whom were taking TKIs only (median age 55, 40% female), and twenty were taking TKI and SSRI concomitantly (median age 53.5, 55% female). Baseline demographics between these groups were similar across all variables. Patients in the TKI only group had 9 bleeding events and 3 thrombotic events. Patients in the combination group had 6 bleeding events and 1 thrombotic event. There was no difference between overall rates of major bleeding (4% v. 10%, p = 0.26) or thrombotic events (4% v. 5%, p = 1). However, patients in the combination group were more likely to have major intracranial bleeding events (0% v. 10%, p = 0.04), and there was a trend to significance for minor bleeding events (7.5% v. 20%, p = 0.11).

CONCLUSIONS

Concomitant use of TKIs and SSRIs does not appear to increase the total risk of bleeding or thrombotic events compared to patients on TKIs only. However, concomitant use of TKIs and SSRIs may increase risk of intracranial bleeding. Further work is needed to fully assess this risk.

Importance of TKI treatment duration in treatment-free remission of chronic myeloid leukemia: results of the D-FREE study

Treatment-free remission (TFR) is a new goal for patients with chronic myeloid leukemia in chronic phase (CML-CP) with a sustained deep molecular response (DMR) to treatment with tyrosine kinase inhibitors (TKIs). However, optimal conditions for successful TFR in patients treated with second-generation (2G)-TKIs are not fully defined. In this D-FREE study, treatment discontinuation was attempted in newly diagnosed CML-CP patients treated with the 2G-TKI dasatinib who achieved BCR-ABL1 levels of ≤ 0.0032% (MR4.5) on the international scale (BCR-ABL1IS) and maintained these levels for exactly 1 year. Of the 173 patients who received dasatinib induction therapy for up to 2 years, 123 completed and 60 (48.8%) reached MR 4.5. Among the first 21 patients who maintained MR4.5 for 1 year and discontinued dasatinib, 17 experienced molecular relapse defined as loss of major molecular response (BCR-ABL1IS > 0.1%) confirmed once, or loss of MR4 (BCR-ABL1IS > 0.01%) confirmed on 2 consecutive assessments. The estimated molecular relapse-free survival rate was 16.7% at 12 months. This study was prematurely terminated according to the protocol's safety monitoring criteria. The conclusion was that sustained DMR for just 1 year is insufficient for TFR in CML-CP patients receiving dasatinib for less than a total of 3 years of treatment.

Protocol for isolation and analysis of the leukemia stem cells in BCR-ABL-driven chronic myelogenous leukemia mice

Practical procedures for sorting and analysis of leukemia stem cells (LSCs) are to improve our understanding of chronic myelogenous leukemia (CML). Here, we present a detailed magnetic-bead-based sorting and flow-cytometry-based analysis protocol for LSCs in BCR-ABL-driven CML mice. We describe steps for sorting and functional analysis of BCR-ABL-expressing c-Kit+ cells (GFP+c-Kit+) from CML mice as well as antibody staining and gating strategies for characterization of leukemia stem/progenitor cells and myeloid leukemia cells. For complete details on the use and execution of this protocol, please refer to Liu et al. (2022).1.

NOX2 and NOX4 control mitochondrial function in chronic myeloid leukaemia

Cancer cells are characterised by an elevated metabolic plasticity and enhanced production of reactive oxygen species (ROS), two features acknowledged as hallmarks in cancer, with a high translational potential to the therapeutic setting. These aspects, that have been traditionally studied separately, are in fact intimately intermingled. As part of their transforming activity, some oncogenes stimulate rewiring of metabolic processes, whilst simultaneously promoting increased production of intracellular ROS. In this scenario the latest discoveries suggest the relevance of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX) to connect ROS production and metabolic control. Here we have analysed the relevance of NOX2 and NOX4 in the regulation of metabolism in chronic myeloid leukaemia (CML), a neoplasia driven by the expression of the breakpoint cluster region-Abelson fusion oncogene (BCR-ABL). Silencing of NOX2 enhances glycolysis and oxidative phosphorylation rates, together with an enhanced production of mitochondrial ROS and a decrease in mitochondrial DNA copy number, which reflects mitochondrial dysfunction. NOX4 expression was upregulated upon NOX2 silencing, and this was required to alter mitochondrial function. Our results support the relevance of NOX2 to regulate metabolism-related signalling pathways downstream of BCR-ABL. Overall we show that NOX2, through the regulation of NOX4 expression, controls metabolism and mitochondrial function in CML cells. This notion was confirmed by transcriptomic analyses, that strongly relate both NOX isoforms with metabolism regulation in CML.

mTORC2 Is Activated under Hypoxia and Could Support Chronic Myeloid Leukemia Stem Cells

Hypoxia is a critical condition that governs survival, self-renewal, quiescence, metabolic shift and refractoriness to leukemic stem cell (LSC) therapy. The present study aims to investigate the hypoxia-driven regulation of the mammalian Target of the Rapamycin-2 (mTORC2) complex to unravel it as a novel potential target in chronic myeloid leukemia (CML) therapeutic strategies. After inducing hypoxia in a CML cell line model, we investigated the activities of mTORC1 and mTORC2. Surprisingly, we detected a significant activation of mTORC2 at the expense of mTORC1, accompanied by the nuclear localization of the main substrate phospho-Akt (Ser473). Moreover, the Gene Ontology analysis of CML patients' CD34+ cells showed enrichment in the mTORC2 signature, further strengthening our data. The deregulation of mTOR complexes highlights how hypoxia could be crucial in CML development. In conclusion, we propose a mechanism by which CML cells residing under a low-oxygen tension, i.e., in the leukemia quiescent LSCs, singularly regulate the mTORC2 and its downstream effectors.

Precision Medicine in Therapy of Non-solid Cancer

The development and approval of the tyrosine kinase inhibitor imatinib in 2001 has heralded the advance of directed therapy options. Today, an armamentarium of targeted therapeutics is available and enables the use of precision medicine in non-solid cancer. Precision medicine is guided by the detection of tumor-specific and targetable characteristics. These include pathogenic fusions and/or mutations, dependency on specific signaling pathways, and the expression of certain cell surface markers. Within the first part, we review approved targeted therapies for the compound classes of small molecule inhibitors, antibody-based therapies and cellular therapies. Particular consideration is given to the underlying pathobiology and the respective mechanism of action. The second part emphasizes on how biomarkers, whether they are of diagnostic, prognostic, or predictive relevance, are indispensable tools to guide therapy choice and management in precision medicine. Finally, the examples of acute myeloid leukemia, chronic lymphocytic leukemia, and chronic myeloid leukemia illustrate how integration of these biomarkers helps to tailor therapy.

Incidence and Bayesian Mapping of Myeloid Hematologic Malignancies in Sardinia, Italy

BACKGROUND

The epidemiology of myeloid hematologic malignancies in Italy has been poorly investigated.

METHODS

We used a validated database of 1974-2003 incident cases of hematologic malignancies among the resident population (all ages) of Sardinia, Italy, to describe the incidence of myeloid malignancies overall (N = 4389 cases) and by subtype. We investigated the time trend of acute myeloid leukemia (N = 1227 cases), chronic myeloid leukemia (N = 613 cases), and myelodysplastic syndrome (N = 1296 cases), and used Bayesian methods to explore their geographic spread, and Poisson regression analysis to estimate their association with environmental and socio-economic factors.

RESULTS

The annual standardized (world population) incidence rate (IR) of myeloid malignancies over the study period was 6.5 per 100,000 (95% CI 6.2-6.7). Myelodysplastic syndromes were the most prevalent subgroup (IR = 1.7, 95% CI 1.5-1.8). Incidence of all myeloid malignancies combined increased sharply during the study period with an annual percent change (APC) of 10.06% (95% CI 9.51-10.61), 19.77% for myelodysplastic syndromes (95% CI 19.63-19.91), and 3.18% (95% CI 2.99-3.37) for acute myeloid leukemia. Chronic myeloid leukemia did not show an upward trend. Apart from sporadic excesses in small rural communities and the major urban area, there was no evidence of spatial clustering. The risk of myeloid malignancies increased with increasing prevalence of sheep breeding.

CONCLUSIONS

Our results might prompt further research on the local genetic and environmental determinants of myeloid hematologic malignancies.

Cell Contact with Endothelial Cells Favors the In Vitro Maintenance of Human Chronic Myeloid Leukemia Stem and Progenitor Cells

Chronic Myeloid Leukemia (CML) originates in a leukemic stem cell that resides in the bone marrow microenvironment, where they coexist with cellular and non-cellular elements. The vascular microenvironment has been identified as an important element in CML development since an increase in the vascularization has been suggested to be related with poor prognosis; also, using murine models, it has been reported that bone marrow endothelium can regulate the quiescence and proliferation of leukemic stem and progenitor cells. This observation, however, has not been evaluated in primary human cells. In this report, we used a co-culture of primitive (progenitor and stem) CML cells with endothelial colony forming cells (ECFC) as an in vitro model to evaluate the effects of the vascular microenvironment in the leukemic hematopoiesis. Our results show that this interaction allows the in vitro maintenance of primitive CML cells through an inflammatory microenvironment able to regulate the proliferation of progenitor cells and the permanence in a quiescent state of leukemic stem cells.

Acute Megakaryoblastic Leukemia Harboring a Subclone Expressing BCR-ABL1 Fusion Gene Product

Acute myeloid leukemia (AML) with BCR-ABL1, also termed Philadelphia chromosome-positive AML (Ph+ AML), is a rare leukemia subtype classified by the World Health Organization in 2016. The characteristics of Ph+ AML have not been fully identified yet. We herein report a patient with Ph+ AML who phenotypically exhibited megakaryoblastic characteristics, FAB:M7 and harbored a subclone expressing BCR-ABL1 gene fusion products. This case suggests that BCR-ABL1 was acquired as a subclone due to a secondary event that might have occurred late during leukemia evolution. Our findings may aid in deciphering the mechanism underlying Ph+ AML development in future studies.

[Preliminary study on the effect of B7H3 interaction with fibronectin on apoptosis of human chronic myeloid leukemia cells]

Objective: To explore the effect of the interaction between B7H3 and fibronectin (FN) on the apoptosis of human chronic myeloid leukemia K562 cells. Methods: The expression of B7H3 molecules in K562 cells was detected using flow cytometry and B7H3 overexpressing cells were constructed. The interaction between B7H3 and FN was detected using the co-immunoprecipitation technology. After adding exogenous FN, cell experiments were performed to detect changes in adhesion and cell apoptosis. The changes in apoptosis-related proteins and PI3K/AKT signaling pathway were detected using Western blot. Results: The expression of B7H3 was low in K562, and the cell line K562 OE (overexpression) -B7H3 and the control cell line K562 NC (negative control) -B7H3 were obtained after lentivirus transfection. There is an interaction between B7H3 and FN (P=0.036) , and this interaction promoted cell adhesion (P<0.05) , inhibited cell apoptosis (P<0.05) , and activated the PI3K/AKT signaling pathway (P<0.05) . Conclusion: B7H3 interacts with FN to promote cell adhesion and may inhibit K562 cell apoptosis by activating the PI3K/AKT signaling pathway.

Galactosaemia occurring in association with primary ovarian insufficiency, Addison's disease and chronic myeloid leukaemia

Classic galactosaemia is the most severe type, inherited in an autosomal recessive fashion and normally detected on newborn screening. It is caused by an inability to digest galactose due to a deficiency of galactose-1-phosphate uridyltransferase (GALT), resulting in an intolerance of feeds in the neonatal period, failure to thrive, hypoglycaemia, jaundice, cataracts, hepatomegaly, vomiting, diarrhoea, developmental delay and an increased risk of Escherichia coli sepsis. The long-term sequelae of this disorder include cognitive impairment, neurological symptoms, such as ataxia, nutritional deficiencies, such as calcium and vitamin D, and gonadal dysfunction. We report here a case of a 34-year-old woman with classic galactosaemia diagnosed in adulthood, developing primary ovarian insufficiency and osteoporosis as well as primary adrenal insufficiency and chronic myeloid leukaemia, which are two associations not seen in current literature. Further studies are needed to determine if an association exists between these diseases.

Changes of Dentition State in Leukemic Patients during Chemotherapy

A number of systemic diseases including hematological disorders have manifestations in the oral cavity region. These manifestations may often represent early signs of the underlying hematopoietic disease and occur frequently in leukemia. Despite the fact that leukemia has long been known to be associated with oral health deterioration, the available literature on this topic consists mostly of case reports, without data to conclude these. The aim of the study was to assess dentition state in leukemic patients during one cycle of chemotherapy and its correlation with blood parameters. The study included 102 adults treated because of leukemia at the Clinic of Haemato-Oncology and Bone Marrow Transplantation at the university hospital in Lublin, Poland. The sample group consisted of 51 women and 51 men aged 22 to 72 (54.07 ± 10.33) with following diagnoses: Acute myelogenous leukemia (AML)-55 patients (53.92%), Chronic lymphocytic leukemia (CLL)-17 patients (16.67%), Acute lymphoblastic leukemia (ALL)-16 patients (15.69%), Chronic myelogenous leukemia (CML)-10 patients (9.80%), Acute promyelocytic leukemia (APL) -3 patients (2.94%), Chronic hairy cell leukemia (HCL)-1 patient (0.98%). DMFT index was used to assess dentition state. After the cycle of chemotherapy, their dentition state changed in terms of decayed, missing and filled teeth and correlated with hematological parameters. Adult patients with leukemia have high dental treatment needs, and high number of missing teeth; thus, a comprehensive and fast dental treatment is necessary to avoid systemic complications and ensure better quality of life.

The effects of oral anticancer parity laws on out-of-pocket spending and adherence among commercially insured patients with chronic myeloid leukemia

BACKGROUND: Over the past 12 years, 43 states and Washington DC have implemented oral anticancer medication parity laws in response to the burden of pharmacy cost sharing. Parity laws are designed to provide equal coverage and cost sharing between orally and parenterally administered anticancer medications for patients in commercial, fully insured health plans (FIHPs). However, there is considerable state-level variation in the requirements to achieve compliance with parity laws, and the clinical and economic effectiveness of parity is not fully known. OBJECTIVES: To (a) understand the impact of parity laws on out-of-pocket (OOP) spending and adherence to tyrosine kinase inhibitors (TKI) among commercially insured patients with chronic myeloid leukemia (CML) and (b) compare these effects across states with and without per prescription or per 30-day OOP spending limits as part of their parity laws. METHODS: Patients aged 18-64 years with CML, at least 1 pharmacy claim for a TKI, and residence in a state that implemented oral anticancer parity legislation between January 1, 2007, and January 1, 2017, were identified from the IBM MarketScan Commercial Claims and Encounters database. A propensity score-weighted difference-in-difference approach was used to measure the impact of parity on OOP spending and adherence in the 6 months after the first pharmacy claim for a TKI (index date) for patients enrolled in FIHPs (subject to parity) and self-funded health plans (SFHPs; exempt from parity). OOP spending was standardized to a 30-day equivalent amount and adjusted to 2017 US dollars. Adherence was assessed using the proportion of days covered (PDC), and patients were categorized as adherent with PDC ≥ 0.80. RESULTS: Of 1,887 patients initiating a TKI before or after their state's parity law, 678 (35.9%) were enrolled in FIHPs (480 before vs 198 after parity), and 1,209 (64.1%) were enrolled in SFHPs (688 before vs 521 after parity). Implementation of parity laws was not associated with any changes in mean OOP spending; however, it was associated with a reduced likelihood of paying $0 per 30 days across all states (adjusted difference-in-difference [aDD] OR = 0.662; 95% CI = 0.535-0.820) and states without OOP spending limits (aDD OR = 0.654; 95% CI = 0.508-0.848), but not in states with limits. Nonsignificant but directionally opposite changes at each end of the OOP spending distribution were observed for states with and without OOP spending limits, with increased spending observed at the 75th, 90th, and 95th percentiles in states without limits. Mean PDC and adherence showed a nonsignificant increase among FIHP and SFHP patients across all states, states with limits, and states without limits. CONCLUSIONS: Oral anticancer parity laws are not associated with reduced OOP spending or improved adherence in a commercially insured sample of patients with CML. These findings were consistent for states that included OOP spending limits as a component of their parity laws. DISCLOSURES: This study did not receive any external funding. Spargo, Yost, Raju, and Schroader are or were employees of Xcenda, which receives contracts from various industry partners unrelated to this work. There are no other conflicts of interest to disclose.

Dynamics of competing heterogeneous clones in blood cancers explains multiple observations - a mathematical modeling approach

Heterogeneity of stem cell clones provide a key ingredient in altered hematopoiesis and is of main interest in the study of predisease states as well as in the development of blood cancers such as chronic myeloid leukemia (CML) and the Philadelphia-negative myeloprofilerative neoplasms (MPNs). A mathematical model based on biological mechanisms and basic cell descriptors such as proliferation rates and apoptosis rates is suggested, connecting stem cell dynamics with mature blood cells and immune mediated feedback. The flexible approach allows for arbitrary numbers of mutated stem cell clones with perturbed properties. In particular, the stem cell niche provides a competition between wild type and mutated stem cells. Hence, the stem cell niche can mediate suppression of the wild type clones and up-regulation of one or more malignant clones. The model is parameterized using clinical data to show typical disease progression in several blood cancers and the hematological and molecular response to treatment. Intriguingly, occasional oscillatory cell counts observed during treatment of CML and MPNs can be explained by heterogeneous stem cell clone dynamics. Thus, the vital heterogeneous stem cell dynamics may be inferred from mathematical modeling in synergy with clinical data to elucidate hematopoiesis, blood cancers and the outcome of interventions.

Time to health-related quality of life improvement analysis was developed to enhance evaluation of modern anticancer therapies

OBJECTIVES

Major advances have recently been made in the treatments of cancer, which now also have the potential to improve patients' health-related quality of life (HRQOL). We propose the time to HRQOL improvement (TTI) and the time to sustained HRQOL improvement (TTSI) as potentially important cancer outcomes to be used in longitudinal HRQOL analyses.

STUDY DESIGN AND SETTING

As proof of principle, we defined TTI and TTSI, using the Fine-Gray model to include competing risks in estimates, in a case study in real life of a cohort of newly diagnosed patients with cancer receiving a targeted therapy. HRQOL was evaluated before and during therapy with six assessments over a 24-month period, using the well-validated European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30.

RESULTS

For each assessed HRQOL domain, we assessed TTI and TTSI and estimated the cumulative incidence of patients' clinically meaningful improvements, also accounting for the occurrence of competing events.

CONCLUSION

TTI and TTSI are potentially important outcomes in the era of modern anticancer therapies. The analysis of TTI and TTSI by competing risks approach will further add to the statistical methods that can be used to inform on the impact of cancer therapies on patients' HRQOL.

Competing endogenous RNA regulation in hematologic malignancies

The clinical application of cytogenetic analysis and molecular-targeted drugs has dramatically improved the prognosis for many patients with hematologic malignancy, especially for those with chronic myeloid leukemia (CML) and acute promyelocytic leukemia (APL). Nevertheless, the treatment of hematologic malignancies is still faced with problems, such as disease recurrence and drug resistance, so further exploring the underlying molecular mechanism is urgent. With the discovery of different RNA species, the mechanism of RNA-RNA interaction has caught more and more attention. "Competing endogenous RNA (ceRNA) hypothesis" is one of the fascinating products of recent researches. CeRNAs are endogenous RNA transcripts that share mutual microRNA response elements (MREs) and regulate expression of each other by competing for the same microRNAs pools. The hypothesis links different RNA species together and enriches our understanding of the human genome. Here, we introduce the hypothesis critically, summary the research progress in the field of hematologic malignancies and the current investigation methods, and address its promising clinical value in offering new predictive, prognostic biomarkers and therapeutic targets.

[18F-fluorodeoxyglucose-positron emission tomography imaging before and after treatment of chronic-phase chronic myeloid leukemia with tyrosine kinase inhibitors]

A 64-year-old man presented with abnormal imaging results on 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET), showing moderately increased FDG-uptake in the entire bone marrow. Blood tests revealed leukocytosis, thrombocytosis, and increased lactate dehydrogenase levels. Furthermore, the neutrophil alkaline phosphatase score decreased. Bone marrow examination revealed marked hypercellularity of myeloid and megakaryocytic lineages without an excess of blasts. Cytogenetic analysis of the bone marrow demonstrated Philadelphia chromosome, and fluorescence in situ hybridization analysis was positive for BCR-ABL1 fusion genes. Thus, the patient was diagnosed with chronic myeloid leukemia (CML) in the chronic phase and tyrosine kinase inhibitor therapy with 100 mg of dasatinib daily was initiated. Complete cytogenetic response and a major molecular response were achieved at 3 and 12 months post-treatment, respectively. FDG-uptake values of the bone marrow remarkably decreased along with the remission status of the disease. FDG-PET images at pre- and post-treatment of CML are rarely compared, so we report this case as an important reference.

[A Case of Philadelphia Chromosome-Positive Acute Myeloid Leukemia Extramedullary Recurrence in a Patient Undergoing Thoracoscopy for Massive Pleural Effusion]

A man in his early 70s visited a previous hospital because of pancytopenia and was diagnosed with acute myeloid leukemia based on a bone marrowexamination. The karyotype was 46,XY, t(9;22)(q34;q11.2)[2/20], and real-time polymerase chain reaction(PCR)revealed minor bcr-abl chimeric mRNA. Finally, the patient was judged as having Philadelphia chromosome- positive acute myeloid leukemia, and remission induction chemotherapy with the JALSG AML 201 protocol was initiated in combination with dasatinib to achieve complete remission. After 3 courses of consolidation chemotherapy, the anticancer drugs were discontinued because of deterioration of his general condition and renal insufficiency. Six months after the initial treatment, he was referred to our department, and no evidence of recurrence was confirmed on bone marrow examination. However, 2 months later, right massive pleural effusion was detected, and he was admitted to the department of pneumology at our hospital. Thoracoscopic pleural biopsy was performed at the time of chest tube insertion, and he was diagnosed with acute myeloid leukemia extramedullary recurrence. Peripheral myeloblasts appeared and increased rapidly, accompanied by further exacerbation of renal function; thus, he received palliative care at the department of hematology and oncology.

[Fertility and disease outcomes in patients with chronic myeloid leukemia]

Objective: To explore Fertility and disease outcomes in patients with chronic myeloid leukemia (CML) . Methods: Clinical and fertility outcomes of male (from Jul. 1998 to Feb. 2018) and female CML (from Sep. 2009 to Feb. 2018) patients were retrospectively analyzed at Peking University People's Hospital. Results: A total of 49 male CML patients and their spouses were enrolled. Before their spouses conceived, 34 patients were receiving tyrosine kinase inhibitor (TKI) imatinib, 9 with nilotinib, and 6 with dasatinib. At the time of conception, the median age of these male patients was 32 years (range, 25-48 years) , and the median TKI treatment duration was 36 months (range, 0.2-198 months) . One male patient having achieved complete hematologic response yet discontinuing TKI for a year developed a disease progression to blast crisis. The other 48 patients sustained stable disease. The total conception times were 61 and finally 55 infants were born including one with premature birth, two with low birth weight, and one with hypospadias receiving surgery. The other 18 female patients after pregnancy were enrolled. Two patients developed spontaneous abortions. Two received induced abortions. Fourteen gave birth to healthy infants without congenital malformation. The interval from diagnosis of CML to initiation of TKI was 4 months (range, 0.3-16 months) . During a median follow-up of 45 months (range from 7-114 months) , the estimated complete cytogenetic response (CCyR) rate, major molecular response (MMR) rate and molecular response(4.5) (MR(4.5)) rate by 5 years were 88.9%, 85.3% and 35.1%, respectively. The estimated failure-free survival, progression-free survival and overall survival were 64.2%, 90.9% and 90.9%, respectively. All 14 babies developed as normal. Conclusions: It seems that TKIs do not affect pregnancy outcome in the spouses of male CML patients, suggesting that withdrawal of TKIs is not necessary. Female CML patients have good pregnancy and disease outcomes in the TKI era.

Tumor Cell Dormancy-Triggered by the Niche

Dormant cancer cells often survive treatment and increase the risk for tumor relapse, associated with dismal prognosis. Two recent papers describe mechanisms used by the bone marrow niche to regulate leukemia dormancy. The findings provide a molecular basis for niche-targeting therapies that may enable elimination of dormant tumor cells.