Risk of hepatitis B virus reactivation in oncological patients treated with tyrosine kinase inhibitors:A case report and literature analysis

Hepatitis B virus(HBV)reactivation(HBVr)represents a severe and potentially life-threatening condition,and preventive measures are available through blood test screening or prophylactic therapy administration.The assessment of HBVr traditionally considers factors such as HBV profile,including hepatitis B surface antigen(HBsAg)and antibody to hepatitis B core antigen,along with type of medication(chemotherapy;immunomodulants).Nevertheless,consideration of possible patient’s underlying tumor and the specific malignancy type(solid or hematologic)plays a crucial role and needs to be assessed for decision-making process.

Navigating the complex terrain of hepatitis B virus reactivation in the era of Bruton tyrosine kinase inhibitors

In this editorial,we offer a summary of the risk associated with hepatitis B reactivation(HBVr)in the setting of both solid and hematologic malignancies treated with Bruton tyrosine kinase(BTK)inhibitors,with insights derived from current studies.Furthermore,we emphasize the critical need for a framework regarding robust risk evaluation in patients undergoing such treatments.This framework is essential for identifying those at increased risk of HBVr,enabling healthcare providers to implement proactive measures to prevent reactivation and ensure the safe administration of BTK inhibitor therapy.

Bruton’s tyrosine kinase inhibitors in primary central nervous system lymphoma:New hopes on the horizon

In this editorial,we comment on the article by Wang et al.This manuscript explores the potential synergistic effects of combining zanubrutinib,a novel oral inhibitor of Bruton’s tyrosine kinase,with high-dose methotrexate(HD-MTX)as a therapeutic intervention for primary central nervous system lymphoma(PCNSL).The study involves a retrospective analysis of 19 PCNSL patients,highlighting clinicopathological characteristics,treatment outcomes,and genomic biomarkers.The results indicate the combination’s good tolerance and strong antitumor activity,with an 84.2%overall response rate.The authors emphasize the potential of zanubrutinib to modulate key genomic features of PCNSL,particularly mutations in myeloid differentiation primary response 88 and cluster of differentiation 79B.Furthermore,the study investigates the role of circulating tumor DNA in cerebrospinal fluid for disease surveillance and treatment response monitoring.In essence,the study provides valuable insights into the potential of combining zanubrutinib with HD-MTX as a frontline therapeutic regimen for PCNSL.The findings underscore the importance of exploring alternative treatment modalities and monitoring genomic and liquid biopsy markers to optimize patient outcomes.While the findings suggest promise,the study’s limitations should be considered,and further research is needed to establish the clinical relevance of this therapeutic approach for PCNSL.

Effect of a novel tyrosine kinase inhibitor nintedanib on bFGF and VEGF concentrations in a rabbit retinal vein occlusion model

AIM:To evaluate whether a novel tyrosine kinase inhibitor nintedanib could inhibit basic fibroblast growth factor(bFGF)and vascular endothelial growth factor(VEGF)simultaneously for retinal vascular disease in vivo.METHODS:After a laser induced rabbit retinal vein occlusion(RVO)model was made,0.5 mg of nintedanib was injected intravitreally in the left eye on the third day while the right eye was as a control.Intracameral samples were taken on the day before laser treatment and days 1,3,7,14,21,and 28 after treatment.Enzyme-linked immunosorbent assay(ELISA)was used to test the bFGF and VEGF-A concentrations in the aqueous humor.RESULTS:Both bFGF and VEGF-A rose significantly on the third day after laser treatment in both eyes.In the control eye the bFGF concentration peaked on the 14th day while the VEGF-A concentration dropped rapidly soon after the third day.After nintadanib injection in the study eye,both bFGF and VEGF-A showed a significant reduction on the 4th day(7th day after laser treatment)when compared to the control eye,and kept on low level in the following several weeks.CONCLUSION:Intravitreal injection of nintedanib can inhibit the expression of bFGF and VEGF in the process of RVO model to a certain extent,which is expected to become a new method for the treatment of retinal vascular diseases or fibrotic diseases.

Tyrosine kinase inhibitors and human epidermal growth factor receptor-2 positive breast cancer

The body of evidence investigating human epidermal growth factor receptor-2(HER2)directed therapy in patients with breast cancer(BC)has been growing within the last decade.Recently,the use of tyrosine kinase inhibitors(TKIs)has been of particular interest in the treatment of human malignancies.This literature commentary is intended to highlight the most recent findings associated with the widely-studied TKI agents and their clinical significance in improving the outcomes of HER2 positive BC.

Rituximab combined with Bruton tyrosine kinase inhibitor to treat elderly diffuse large B-cell lymphoma patients: Two case reports

BACKGROUND Diffuse large B-cell lymphoma(DLBCL)is a common aggressive non-Hodgkin's lymphoma(NHL),accounting for 30%-40%of adult NHLs.This report aims to explore the efficacy and safety of rituximab combined with Bruton tyrosine kinase inhibitors(BTKis)in the treatment of elderly patients with DLBCL.CASE SUMMARY The clinical data of two elderly patients with DLBCL who received rituximab combined with BTKi in our hospital were retrospectively analyzed,and the literature was reviewed.The patients were treated with chemotherapy using the R-miniCHOP regimen for two courses.Then,they received rituximab in combination with BTKi.CONCLUSION The treatment experience in these cases demonstrates the potential efficacy of rituximab combined with BTKi to treat elderly DLBCL patients,thus providing a new treatment strategy.

ABNORMAL PROTEIN TYROSINE KINASES ASSOCIATED WITH HUMAN HAEMATOLOGICAL MALIGNANCIES

Objective: To survey the role of protein tyrosine kinases (PTKs) in the pathogenesis of several hematopoietic malignancies. Methods: By reviewing the published laboratory and clinical studies on PTK-related oncoproteins and their causative role in some leukemias and lymphomas. Results: Protein tyrosine kinases are key participants in signal transduction pathways that regulate cellular growth, activation and differentiations. Aberrant PTK activity resulting from gene mutation (often accompanying chromosome translocation) plays an etiologic role in several clonal hematopoietic malignancies. For example, the PTK product of the BCR-ABL fusion gene resulting from the t (9; 22) translocation exhibits several fold higher tyrosine kinase activity than the product of the ABL gene. Evidence suggests that the BCR-ABL oncoprotein alone is sufficient to case chronic myelogenous leukemia (CML) and other Ph positive acute leukemia. PTK over-activity resulting from chromosomal translocations creating TEL-ABL, TEL-JAK2 and TEL-PDGFRβ fusion proteins plays an important role in the pathogenesis of other types of leukemia. Another example occurs in anaplastic large cell lymphoma (ALCL). Experimental and clinical evidences indicate that translocations involving ALK gene on chromosome 2p23, most commonly resulting in an NPM-ALK fusion oncogene, result in constitutive activation of ALK and cause ALCL. This group of lymphomas is now named ALK positive lymphoma or ALKoma. Conclusion: Genetic lesions creating aberrant fusion proteins that result in excessive PTK activity are increasingly being recognized as central to the pathogenesis of hemotopoietic malignancies. These chimeric PTK molecules represent attractive disease-specific targets against which new classes therapeutic agents are being developed.

Role of spleen tyrosine kinase in liver diseases

Spleen tyrosine kinase (SYK),a non-receptor tyrosine kinase,is expressed in most hematopoietic cells and non-hematopoietic cells and play a crucial role in both immune and non-immune biological responses.SYK mediate diverse cellular responses via an immune-receptor tyrosine-based activation motifs (ITAMs)-dependent signalling pathways,ITAMs-independent and ITAMs-semidependent signalling pathways.In liver,SYK expression has been observed in parenchymal (hepatocytes) and non-parenchymal cells (hepatic stellate cells and Kupffer cells) and found to be positively correlated with the disease severity.The implication of SYK pathway has been reported in different liver diseases including liver fibrosis,viral hepatitis,alcoholic liver disease,non-alcoholic steatohepatitis and hepatocellular carcinoma.Antagonism of SYK pathway using kinase inhibitors have shown to attenuate the progression of liver diseases thereby suggesting SYK as a highly promising therapeutic target.This review summarizes the current understanding of SYK and its therapeutic implication in liver diseases.

Pathogenesis of RON receptor tyrosine kinase in cancer cells: activation mechanism, functional crosstalk, and signaling addiction

The RON receptor tyrosine kinase, a member of the MET proto-oncogene family, is a pathogenic factor im- plicated in tumor malignancy. Specifically, aberrations in RON signaling result in increased cancer cell growth, survival, invasion, angiogenesis, and drug resistance. Biochemical events such as ligand binding, receptor over- expression, generation of structure-defected variants, and point mutations in the kinase domain contribute to RON signaling activation. Recently, functional crosstalk between RON and signaling proteins such as MET and EFGR has emerged as an additional mechanism for RON activation, which is critical for tumorigenic develop- ment. The RON signaling crosstalk acts either as a regulatory feedback loop that strengthens or enhances tumor- igenic phenotype of cancer cells or serves as a signaling compensatory pathway providing a growth/survival ad- vantage for cancer cells to escape targeted therapy. Moreover, viral oncoproteins derived from Friend leukemia or Epstein-Barr viruses interact with RON to drive viral oncogenesis. In cancer cells, RON signaling is integrated into cellular signaling network essential for cancer cell growth and survival. These activities provide the mo- lecular basis of targeting RON for cancer treatment. In this review, we will discuss recent data that uncover the mechanisms of RON activation in cancer cells, review evidence of RON signaling crosstalk relevant to cancer malignancy, and emphasize the significance of the RON signaling addiction by cancer cells for tumor therapy. Understanding aberrant RON signaling will not only provide insight into the mechanisms of tumor pathogenesis, but also lead to the development of novel strategies for molecularly targeted cancer treatment.

Effects of tyrosine kinase inhibitor E7080 and eNOS inhibitor L-NIO on colorectal cancer alone and in combination

Objective：To investigate the effects of E7080 and N5-（1-iminoethyl）-L-ornithine dihydrochloride （L-NIO）on colorectal cancer alone and in combination.Methods：HT29 colorectal cancer cell line from Sap Institute was used.Real-time cell analysis （xCELLigence system） was performed to determine the effects of E7080 and L-NIO on colorectal cell proliferation.While apoptosis was determined with Annexin V staining,and the effect of agents on angiogenesis was determined with chorioallantoic membrane （CAM） model.Results：We found that E7080 has a strong antiproliferative effect with an half maximum inhibition of concentration （IC50） value of 5.60×10-8 mol/L.Also it has been observed that E7080 showed antiangiogenic and apoptotic effects on HT29 colorectal cancer cells.Antiangiogenic scores of E7080 were 1.2,t.0 and 0.6 for 100,10 and 1 nmol/L E7080 concentrations,respectively.Furthermore,apoptosis has been detected in 71％ of HT29 colorectal cancer cells after administration of 100 nmol/L E7080 which may indicate strong apoptotic effect.Meanwhile administration of L-NIO alone did not show any effect,but the combination of E7080 with L-NIO increased the antiproliferative,antiangiogenic and apoptotic effects of E7080.Conclusions：Results of this study indicate that E7080 may be a good choice in treatment of colorectal tumors.Furthermore the increased effects of E7080 when combined with L-NIO raise the possibility to use a lower dose of E7080 and therefore avoid/minimize the side effects observed with E7080.

Inhibitory effects of regorafenib, a multiple tyrosine kinase inhibitor, on corneal neovascularization

AIM:To evaluate the inhibitory effects of regorafenib(BAY 73-4506),a multikinase inhibitor,on corneal neovascularization(NV).METHODS:Thirty adult male Sprague-Dawley rats weighing 250-300 g,were used.Corneal NV was induced by NaOH in the left eyes of each rat.Following the establishment of alkali burn,the animals were randomized into five groups according to topical treatment.Group 1(n=6)received 0.9%NaCl,Group 2(n=6)received dimethyl sulfoxide,Group 3(n=6)received regorafenib 1 mg/mL,Group 4(n=6)received bevacizumab 5 mg/mL and Group 5(n=6)received 0.1%dexamethasone phosphate.On the 7d,the corneal surface covered with neovascular vessels was measured on photographs as the percentage of the cornea’s total area using computer-imaging analysis.The corneas obtained from rats were semiquantitatively evaluated for caspase-3 and vascular endothelial growth factor by immunostaining.RESULTS:A statistically significant difference in the percent area of corneal NV was found among the groups(P【0.001).Although the Group 5 had the smallest percent area of corneal NV,there was no difference among Groups 3,4 and 5(P】0.005).There was a statistically significant difference among the groups in apoptotic cell density(P=0.002).The staining intensity of vascular endothelial growth factor in the epithelial and endothelial layers of cornea was significantly different among the groups(P【0.05).The staining intensity of epithelial and endothelial vascular endothelial growth factor was significantly weaker in Groups 3,4 and 5 thanin Groups 1 and 2.CONCLUSION:Topical administration of regorafenib 1mg/mL is partly effective for preventing alkali-induced corneal NV in rats.

Efficacy of EGFR Tyrosine Kinase Inhibitors in Non-small Cell Lung Cancer Patients Harboring Different Types of EGFR Mutations:A Retrospective Analysis

With the development of molecular pathology, many types of epidermal growth factor receptor（EGFR） mutations have been identified. The efficacy of EGFR tyrosine kinase inhibitors（EGFR-TKIs） in non-small cell lung cancer（NSCLC） patients with different types of EGFR mutations, especially in patients with single rare mutations or complex mutations（co-occurrence of two or more different mutations）, has not been fully understood. This study aimed to examine the efficacy of EGFR-TKIs in NSCLC patients with different types of EGFR mutations. Clinical data of 809 NSCLC patients who harbored different types of EGFR mutations and treated from January 2012 to October 2016 at Renmin Hospital and Zhongnan Hospital, Wuhan, were retrospectively reviewed. The clinical characteristics of these patients and the efficacy of EGFR-TKIs were analyzed. Among these patients, 377 patients had only the EGFR del-19 mutation, 362 patients the EGFR L858R mutation in exon 21, 33 patients single rare mutations and 37 patients complex mutations. Among these 809 patients, 239 patients were treated with EGFR-TKIs. In all the 239 patients, the disease control rate（DCR） was 93.7% with two patients（0.2%） achieving complete response（CR）, the median progression free survival（PFS） was 13.0 months（95% confidence interval [CI], 11.6–14.4 months）, and the median overall survival（OS） was 55.0 months（95% CI, 26.3–83.7 months）. Subgroup analysis revealed that the DCR in patients harboring single rare or complex mutations of EGFR was significantly lower than in those with del-19 or L858 R mutation（P〈0.001）. Patients with classic mutations（del-19 and/or L858 R mutations） demonstrated longer PFS（P〈0.001） and OS（P=0.017） than those with uncommon mutations（single rare and/or complex mutations）. Furthermore, the patients with single rare mutations had shorter median OS than in those with other mutations. Multivariate Cox regression analysis identified that the type of EGFR mutations was an independent risk factor for PFS（hazard ratio [HR]=0.308, 95% CI, 0.191–0.494, P〈0.001） and OS（HR=0.221, 95% CI, 0.101–0.480, P〈0.001）. The results suggest that the single rare or complex EGFR mutations confer inferior efficacy of EGFR-TKIs treatment to the classic mutations. The prognosis of the single rare EGFR mutations is depressing. EGFR-TKIs may be not a good choice for NSCLC patients with single rare mutations of EGFR. Further studies in these patients with uncommon mutations（especially for the patients with single rare mutations） are needed to determine a better precision treatment.

Imipramine protects retinal ganglion cells from oxidative stress through the tyrosine kinase receptor B signaling pathway

Retinal ganglion cell（RGC） degeneration is irreversible in glaucoma and tyrosine kinase receptor B（Trk B）-associated signaling pathways have been implicated in the process.In this study,we attempted to examine whether imipramine,a tricyclic antidepressant,may protect hydrogen peroxide（H_2O_2）-induced RGC degeneration through the activation of the Trk B pathway in RGC-5 cell lines.RGC-5 cell lines were pre-treated with imipramine 30 minutes before exposure to H_2O_2.Western blot assay showed that in H_2O_2-damaged RGC-5 cells,imipramine activated Trk B pathways through extracellular signal-regulated protein kinase/Trk B phosphorylation.TUNEL staining assay also demonstrated that imipramine ameliorated H_2O_2-induced apoptosis in RGC-5 cells.Finally,Trk B-Ig G intervention was able to reverse the protective effect of imipramine on H_2O_2-induced RGC-5 apoptosis.Imipramine therefore protects RGCs from oxidative stress-induced apoptosis through the Trk B signaling pathway.

Threonine and tyrosine kinase may serve as a prognostic biomarker for gallbladder cancer

AIM To detect the expression of threonine and tyrosine kinase(TTK) in gallbladder cancer(GBC) specimens and analyze the associations between TTK expression and clinicopathological parameters and clinical prognosis.METHODS A total of 68 patients with GBC who underwent surgical resection were enrolled in this study. The expression of TTK in GBC tissues was detected by immunohistochemistry. The assessment of TTKexpression was conducted using the H-scoring system. H-score was calculated by the multiplication of the overall staining intensity with the percentage of positive cells. The expression of TTK in the cytoplasm and nucleus was scored separately to achieve respective H-s c o r e v a l u e s. T h e c o r r e l a t i o n s b e t w e e n T T K expression and clinicopathological parameters and clinical prognosis were analyzed using Chi-square test, Kaplan-Meier method and Cox regression.RESULTS In both the nucleus and cytoplasm, the expression of TTK in tumor tissues was significantly lower than that in normal tissues(P < 0.001 and P = 0.026, respectively). Using the median H-score as the cutoff value, it was discovered that, GBC patients with higher levels of TTK expression in the nucleus, but not the cytoplasm, had favorable overall survival(P < 0.001), and it was still statistically meaningful in Cox regression analysis. Further investigation indicated that there were close negative correlations between TTK expression and tumor differentiation(P = 0.041), CA 19-9 levels(P = 0.016), T stage(P < 0.001), nodal involvement(P < 0.001), distant metastasis(P = 0.024) and TNM stage(P < 0.001). CONCLUSION The expression of TTK in GBC is lower than that in normal tissues. Higher levels of TTK expression in GBC are concomitant with longer overall survival. TTK is a favorable prognostic biomarker for patients with GBC.

Immediate Versus Delayed Treatment with EGFR Tyrosine Kinase Inhibitors after First-line Therapy in Advanced Non-small-cell Lung Cancer

Objective： To analyze the outcomes of patients who received TKI immediately after the first-line without progression as maintenance treatment （immediate group） vs. those received delayed treatment upon disease progression as second-line therapy （delayed group）. Methods： The study included 159 no-small-cell lung cancer （NSCLC） patients who received gefitinib or erlotinib as maintenance treatment in the immediate group （85 patients） or as second-line therapy in the delayed group （74 patients）. The primary end point was progression-free survival （PFS）. EGFR mutation status was detected using denaturing high-performance liquid chromatography （DHPLC）. Results： PFS was 17.3 and 16.4 months in the immediate and delayed groups, respectively （hazard ratio [HR], 0.99; 95% Confidence Interval [CI]： 0.69-1.42; P=0.947）. In a subgroup analysis that included only patients with EGFR mutation, however, PFS was significantly longer in the immediate group than in the delayed group （HR, 0.48; 95% CI： 0.27-0.85; P=0.012）. In patients with wild type EGFR, the risk for disease progression was comparable between the two groups （HR, 1.23; 95% CI： 0.61-2.51; P=0.564）. No significant difference was demonstrated between the immediate and delayed group in terms of the overall survival （OS） （26.1 months vs. 21.6 months, respectively; HR=0.53; 95% CI： 0.27 to 1.06; P=0.072）. There was also no difference in the incidence of adverse events between the two groups. Conclusions： EGFR TKI maintenance improves PFS in patients with EGFR mutation. Prospectively designed clinical studies that compare TKI immediate vs. delayed treatment after first-line chemotherapy upon disease progression are needed.

Current understanding of the role of tyrosine kinase 2 signaling in immune responses

Immune system is a complex network that clears pathogens,toxic substrates,and cancer cells.Distinguishing self-antigens from non-self-antigens is critical for the immune cell-mediated response against foreign antigens.The innate immune system elicits an early-phase response to various stimuli,whereas the adaptive immune response is tailored to previously encountered antigens.During immune responses,B cells differentiate into antibody-secreting cells,while naïve T cells differentiate into functionally specific effector cells[T helper 1(Th1),Th2,Th17,and regulatory T cells].However,enhanced or prolonged immune responses can result in autoimmune disorders,which are characterized by lymphocytemediated immune responses against self-antigens.Signal transduction of cytokines,which regulate the inflammatory cascades,is dependent on the members of the Janus family of protein kinases.Tyrosine kinase 2(Tyk2)is associated with receptor subunits of immune-related cytokines,such as type I interferon,interleukin(IL)-6,IL-10,IL-12,and IL-23.Clinical studies on the therapeutic effects and the underlying mechanisms of Tyk2 inhibitors in autoimmune or chronic inflammatory diseases are currently ongoing.This review summarizes the findings of studies examining the role of Tyk2 in immune and/or inflammatory responses using Tyk2-deficient cells and mice.

Levetiracetam induces tyrosine kinase receptor B expression in SH-SY5Y cells

Tyrosine kinase receptor B （TrkB） plays an important role in long-term potentiation and memory formation.The present study used all-trans retinoic acid to induce TrkB expression in SH-SY5Y cells,and observed the effects of levetiracetam （LEV） on TrkB expression.Following exposure to 10,50,and 100 μg/mL LEV,the number of TrkB-positive cells,and average absorbance value were increased.Results demonstrated that LEV can induce TrkB expression in SH-SY5Y cells.

Effects of ginsenoside on brain-derived neurotrophic factor and tyrosine kinase B mRNA expression in the hippocampal formation of aged rats

BACKGROUND： There are a limited number of studies involving the effects of ginsenosides, the active component of ginseng, on expression of hippocampal TrkB mRNA in aged rats. OBJECTIVE： To observe expression of brain-derived neurotrophic factor （BDNF） and tyrosine kinase B （TrkB） mRNA in the hippocampal formation of aged rats, as well as changes after ginsenoside administrated. DESIGN, TIME AND SETTING： A randomized, controlled experiment was performed at the Department of Anatomy, College of Basic Medical Sciences, China Medical University in March 2005. MATERIALS： A total of 39 female, Wistar rats were randomly divided into 3 groups （n = 13 each）： young （3-5 months old）, aged （27 months old）, and ginsenoside group （received 25mg/kg/d ginsenoside in the drinking water between 17 and 27 months of age）. METHODS： Following anesthesia, the rats were exsanguinated and perfused transcardially with chilled, heparinized, 0.9% saline. The brains were removed and post-fixed in 40 g/L paraformaldehyde/phosphate buffer for 20 minutes, and further incubated in 30% sucrose/phosphate buffer overnight. MAIN OUTCOME MEASURES： In situ hybridization, immunohistochemistry, and image analysis were used to investigate expression of BDNF and TrkB mRNA in the hippocampal formation. RESULTS： The expression levels of BDNF in the hippocampal CA3 and CA1 of aged rats was significantly less than the young group （t = 2.879, 1.814, 1.984, P 〈 0.05）. BDNF expression was significantly greater in the dentate gyrus of the ginsenoside group, compared with the aging group （t = 1.943, P 〈 0.01）. The expression of TrkB mRNA in the hippocampal CA3, CA1, and dentate gyrus of aged rats was less than the young group （t = 3.540, 3.629, 17.905, P 〈 0.01）. TrkB mRNA expression in the CA3 region and dentate gyrus of the ginsenoside group was significantly greater compared with the aging group （t = 1.293, 3.386, P 〈 0.05, 0.01 ）. CONCLUSION： BDNF and TrkB mRNA expression in the hippocampal formation were reduced in the aged group. However, ginsenosides can increase BDNF and TrkB mRNA expression in the hippocampal formation.

Two sides of the same coin: tyrosine kinase inhibitionin cancer and neurodegeneration

Cancer and neurodegeneration include a group of diseases that are mechanistically distinct but may share common therapeutic targets.Autophagy is a common quality control mechanism shared by mitotic and post-mitotic cells and it can be exploited to accelerate clearance of unwanted oncogenes and reduce accumulation of toxic proteins in cancer and neurodegeneration,respectively.Tyrosine kinase inhibition is a therapeutically relevant strategy that can induce autophagy, leading to normal cell survival. This article provides insights into how tyrosine kinase inhibition is clinically used to arrest mitotic cell division and tumor growth, and may promote survival of post-mitotic neurons in neurodegeneration.

Predictive indicators of successful tyrosine kinase inhibitor discontinuation in patients with chronic myeloid leukemia

Clinical trials have demonstrated that some patients with chronic myeloid leukemia(CML)treated for several years with tyrosine kinase inhibitors(TKIs)who have maintained a molecular response can successfully discontinue treatment without relapsing.Treatment free remission(TFR)can be reached by approximately 50%of patients who discontinue.Despite having similar levels of deep molecular response and an identical duration of treatment,the factors that influence the successful discontinuation of CML patients remain to be determined.In this review we will explore the factors identified to date that can help predict whether a patient will successfully achieve TFR.We will also discuss the need for the identification of predictive biomarkers associated with a high probability of achieving TFR for the future personalized identification of patients who are suitable for the discontinuation of TKI treatment.