Wilms' tumor gene 1 transcript levels in leukapheresis of peripheral blood hematopoietic cells predict relapse risk in patients autografted for acute myeloid leukemia

Day +60 WT1 assessment on CD34 selected bone marrow better predicts relapse and mortality after allogeneic stem cell transplantation in acute myeloid leukemia patients

The aim of this study was to evaluate the role of WT1 expression after allogeneic stem cell transplantation (alloHSCT) in patients with acute myeloid leukemia (AML). We studied WT1 expression in bone marrow cells from 50 patients in complete remission on day +60 after transplant. WT1 was assessed on unfractionated bone marrow mononuclear cells (MNC) and on CD34+ selected cells (CD34+). A ROC curve analysis identified 800 WT1 copies on CD34+ selected cells, as the best cut-off predicting relapse (AUC 0.842, p=0.0006, 85.7% sensitivity and 81.6% specificity) and 100 copies in MNC (AUC 0.819, p=0.007, 83.3% sensitivity and 88.2% specificity). Using the 800 WT1 copy cut off in CD34+ cells, the 2 year cumulative incidence of relapse was 12% vs 38% (p=0.005), and 2 year survival 88% vs 55% (p=0.02). Using the 100 WT1 copy cut off in unfractionated MNC, the 2 year cumulative incidence of relapse 13% vs 44% (p=0.01) and the 2 year survival 88% vs 55% (p=0.08). In a multivariate Cox analysis WT1 expression in CD34 cells proved to highly predictive of relapse (p=0.004); also WT1 expression on unfractionated cells predicted relapse (p=0.03). In conclusion, day-60 WT1 expression after allogeneic HSCT is a significant predictor of relapse, particularly when tested on CD34+ selected bone marrow cells.

The Role of Wilms' Tumor Gene (WT1) Expression as a Marker of Minimal Residual Disease in Acute Myeloid Leukemia

The Minimal Residual Disease(MRD) monitoring in acute myeloid leukemia (AML) is crucial to guide treatment after morphologic complete remission, to define the need for consolidation with allogeneic stem cell transplantation (Allo-SCT), and to detect impending relapse allowing early intervention. However, more than 50% of patients with AML lack a specific or measurable molecular marker to monitor MRD. We reviewed the key studies on WT1 overexpression as a marker of MRD in AML patients undergoing an intensive chemotherapy program, including Allo-SCT. In addition, we provided some practical considerations on how to properly use WT1 expression as an MRD marker, considering its strengths and weaknesses. In order to achieve the best sensitivity and specificity, it is recommended to refer to the standardized method of European LeukemiaNet and its defined threshold (250 WT1 copies/10⁴ Abelson (ABL) on Bone Marrow-BM and 50 WT1 copies/10⁴ ABL on Peripheral Blood-PB), which has been validated in a large and multicenter cohort of patients and normal controls.

History and Development of Autologous Stem Cell Transplantation for Acute Myeloid Leukemia

This review describes the development of cryopreservation, the birth of autologous stem cell transplantation (ASCT) and its past and present use to consolidate adult patients with acute myelogenous leukemia (AML). It summarizes the first autografts in patients in relapse, the experience of autografting in complete remission (CR), using bone marrow unpurged or purged in vitro with cyclophosphamide-derivatives, and the important shift to peripheral blood stem cells. The review also discusses the results of recent studies in favor of the use of ASCT to consolidate good- and intermediate-risk patients who reach CR with no detectable minimal residual disease, and those which support the inclusion of maintenance therapy post autograft with hypomethylating agents, anti-BCL-2, and, possibly, in the future, anti AML chimeric antigen receptor-T cells. Carefully applied to well-selected patients, ASCT may regain interest, because of its simplicity, its reduced toxicity, lower non-relapse mortality and better quality of life.

Somatostatin receptor mediated targeting of acute myeloid leukemia by photodynamic metal complexes for light induced apoptosis

Acute myeloid leukemia (AML) is characterized by relapse and treatment resistance in a major fraction of patients, underlining the need of innovative AML targeting therapies. Here we analysed the therapeutic potential of an innovative biohybrid consisting of the tumor-associated peptide somatostatin and the photosensitizer ruthenium in AML cell lines and primary AML patient samples. Selective toxicity was analyzed by using CD34 enriched cord blood cells as control. Treatment of OCI AML3, HL60 and THP1 resulted in a 92, and 99 and 97% decrease in clonogenic growth compared to the controls. Primary AML cells demonstrated a major response with a 74 to 99% reduction in clonogenicity in 5 of 6 patient samples. In contrast, treatment of CD34⁺ CB cells resulted in substantially less reduction in colony numbers. Subcellular localization assays of RU-SST in OCI-AML3 cells confirmed strong co-localization of RU-SST in the lysosomes compared to the other cellular organelles. Our data demonstrate that conjugation of a Ruthenium complex with somatostatin is efficiently eradicating LSC candidates of patients with AML. This indicates that receptor mediated lysosomal accumulation of photodynamic metal complexes is a highly attractive approach for targeting AML cells.

The Role of Measurable Residual Disease (MRD) in Hematopoietic Stem Cell Transplantation for Hematological Malignancies Focusing on Acute Leukemia

The significance of measurable residual disease (MRD) in hematopoietic stem cell transplantation (HSCT) is well recognized in different hematological malignancies, but the evidence indicate that pre-transplant MRD status is of particular importance in acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). In ALL, inadequate response at the level of MRD is a commonly accepted risk factor for relapse and thus an indication for allogeneic HSCT. Similarly, growing evidence from the literature strongly suggest that MRD detected by multiparameter flow cytometry or molecular techniques should be also used for risk stratification in AML at the time of HSCT. Despite the well-defined association of MRD and outcomes of HSCT in acute leukemias, there are still many open issues such as the role of additional pre-transplant consolidation for MRD eradication, the ability of HSCT to overcome negative influence of MRD positivity on survival, the impact of conditioning regimen intensity on MRD clearance post HSCT, and transplantation outcomes or the selection of optimal donor with regards to MRD status. In addition, the role of MRD assessment in guiding post-transplant maintenance treatment should also be addressed in prospective trials. These open issues mostly awaiting further clinical studies will be discussed in our current review.

Quality of Response in Acute Myeloid Leukemia: The Role of Minimal Residual Disease

In the acute myeloid leukemia (AML) setting, research has extensively investigated the existence and relevance of molecular biomarkers, in order to better tailor therapy with newly developed agents and hence improve outcomes and/or save the patient from poorly effective therapies. In particular, in patients with AML, residual disease after therapy does reflect the sum of the contributions of all factors associated with diagnosis and post-diagnosis resistance. The evaluation of minimal/measurable residual disease (MRD) can be considered as a key tool to guide patient’s management and a promising endpoint for clinical trials. In this narrative review, we discuss MRD evaluation as biomarker for tailored therapy in AML patients; we briefly report current evidence on the use of MRD in clinical practice, and comment on the potential ability of MRD in the assessment of the efficacy of new molecules.

Autologous Hematopoietic Stem Cell Transplantation in Acute Myelogenous Leukemia

The clinical outcomes of autologous hematopoietic stem cell transplantation (ASCT) in acute myelogenous leukemia (AML) have improved over time. Indeed, numerous studies have demonstrated that ASCT is associated with a lower relapse rate and acceptable nonrelapse mortality compared with chemotherapy alone in patients with AML. In addition, ASCT is also associated with comparable overall survival outcomes to those of allogeneic hematopoietic stem cell transplantation in some patients with AML. To date, age, cytogenetic and molecular risk stratification, and minimal residual disease (MRD) status have been shown to be closely related to clinical outcomes following ASCT. ASCT is recommended for patients with favorable-risk and intermediate-risk AML in first complete remission and patients with acute promyelocytic leukemia in second complete remission for whom a matched sibling donor is not available. MRD status pre-ASCT is the most important factor to consider when determining whether a patient is eligible for ASCT and can effectively predict clinical outcomes after ASCT. Advanced age is not an absolute contradiction for ASCT. In this review, we describe the literature and clinical trials evaluating the outcomes of ASCT in patients with AML and discuss the indications for ASCT therapy. Because the greatest concern in ASCT recipients is early relapse, important factors that should be monitored before ASCT and future perspectives in this area are also presented.

Measurable residual disease testing for personalized treatment of acute myeloid leukemia

This review summarizes - with the practicing hematologist in mind - the methods used to determine measurable residual disease (MRD) in everyday practice with some future perspectives, and the current knowledge about the prognostic impact of MRD on outcome in acute myeloid leukemia (AML), excluding acute promyelocytic leukemia. Possible implications for choice of MRD method, timing of MRD monitoring, and guidance of therapy are discussed in general and in some detail for certain types of leukemia with specific molecular markers to monitor, including core binding factor (CBF)-leukemias and NPM1-mutated leukemias.

Autologous Stem Cell Transplantation Is a Viable Postremission Therapy for Intermediate-Risk Acute Myeloid Leukemia in First Complete Remission in the Absence of a Matched Identical Sibling: A Meta-Analysis

BACKGROUND

The preferred type of postremission therapy (PRT) for intermediate-risk acute myeloid leukemia (AML) in first complete remission (CR1) is a subject of continued debate. Although allogeneic stem cell transplantation (alloSCT) is regarded as a curative strategy for AML, the efficacy of autologous stem cell transplantation (autoSCT) for patients without a matched sibling donor (MSD) has remained controversial.

METHODS

To compare survival outcomes after alloSCT versus autoSCT for patients with intermediate-risk AML in CR1, we performed a meta-analysis of 11 clinical studies. The outcomes included relapse-free survival (RFS), overall survival (OS), relapse rate (RR), and treatment-related mortality (TRM).

RESULTS

Compared with autoSCT, alloSCT showed better RFS, OS, and RR benefits, but higher TRM. Subgroup analysis based on donor category (MSD and matched unrelated donor [MUD]) of alloSCT showed alloSCT from MSD rather than from MUD had better OS benefits compared to autoSCT. For fms-like tyrosine kinase 3 internal tandem duplications (FLT3-ITD) wild-type patients, alloSCT and autoSCT had comparable RFS and OS outcomes.

CONCLUSION

Our results suggest that, in the absence of an available MSD, autoSCT remains a viable PRT alternative for intermediate-risk AML in CR1, especially for FLT3-ITD wild-type patients.

Revisiting autologous transplantation in acute myeloid leukemia

PURPOSE OF REVIEW

Autologous hematopoietic cell transplantation (auto-HCT) has been evaluated as a consolidation treatment for acute myeloid leukemia (AML) in the 1980s and 1990s. These prospective studies from large trials compared auto-HCT with chemotherapy. A comparison was made also with allogeneic hematopoietic cell transplantation (allo-HCT). These studies reported a lower relapse rate with auto-HCT compared with chemotherapy, but without impact on the overall survival. A high transplant-related mortality in that era confounded the relevance of these data.

RECENT FINDINGS

Several prospective studies and a plethora of retrospective registry data have confirmed the potent antileukemic therapy of auto-HCT compared with chemotherapy and, in some instances, have even challenged the presumed superiority of allo-HCT as the definitive therapy for certain patients with AML.

SUMMARY

The aggregate of recent data, prospective and retrospective, strongly suggests an important role for auto-HCT, at least as the most potent nonimmunologic antileukemia therapy. The transplant-related mortality in 2017 is close to that expected from standard consolidation therapy leading to the conclusion that the role of auto-HCT needs to be rigorously revisited, preferably in prospective studies, to establish its precise role in the current era.

Optimizing the pretransplant regimen for autologous stem cell transplantation in acute myelogenous leukemia: Better outcomes with busulfan and melphalan compared with busulfan and cyclophosphamide in high risk patients autografted in first complete remission: A study from the acute leukemia working party of the EBMT

Autologous stem cell transplantation remains a clinical option to consolidate some adult patients with acute myelogenous leukemia (AML) in first complete remission (CR1). In a small cohort of patients, we have previously shown better outcomes following Busulfan and Melphalan (BUMEL) over Busulfan and Cyclophosphamide (BUCY). To identify the subpopulations that might get the highest benefit with BUMEL, we designed a larger study. All adult patients with primary AML and available cytogenetics, autografted from January 2000 to December 2016 in CR1, were included: 1137 patients received BUCY and 512 BUMEL. All factors differing in distribution between the 2 conditioning groups were introduced in multivariate analyzes. In a primary analysis, we found an interaction between conditioning and the poor risk group defined as poor cytogenetics and/or presence of the FLT3-ITD mutation. During analysis of the poor risk group, 176 patients received BUCY and 62 BUMEL. BUMEL was associated with a lower RI at 5 years (53% versus 69%, HR: 0.52, P = .002), a better Leukaemia-free survival (LFS) (42% versus 25%, HR: 0.54, P = .002) and a better OS (54% versus 36%, HR: 0.61, P = .02). During analysis of the non poor risk group, 961 patients received BUCY and 450 BUMEL. At 5 years, the RI was 50% and 47%, the LFS 45% and 48% and the OS 56% and 60% respectively, with no significant difference. We conclude that BUMEL is the preferable conditioning regimen for the poor risk leukemic patients, while in AML patients without poor risk cytogenetics or FLT3 both conditioning regimens are valid.

Unrelated matched versus autologous transplantation in adult patients with good and intermediate risk acute myelogenous leukemia in first molecular remission

Patients with Acute Myelogenous Leukemia have a better outcome if reaching molecular remission. We compared the outcome of 373 patients autografted and 335 patients allografted with a 10/10 compatible unrelated donor in first molecular remission. Patients were stratified using the ELN European Leukemia Net classification. ELN favorable group: (234 auto and 70 unrelated transplants). By univariate analysis, in the auto group, the Non Relapse Mortality (NRM) was lower (3.7% versus 19%; P < 10^-4 ), Relapse Incidence (RI) higher (29% versus 17%, P < 10^-4 ), Leukemia Free Survival (LFS) identical (67% versus 64%) and Overall Survival (OS) better than in the allogeneic group (83% versus 62%; P = .008). By multivariate analysis, autologous transplantation was associated with a lower NRM (HR: 4, P = .01) and a better OS (HR: 2.08, P = .04). ELN intermediate group 1: (87 autologous and 172 unrelated transplants). By univariate analysis, in the auto group, NRM was lower (2.5% versus 11.8%; P = .03), RI higher (59% versus 18%, P < 10^-6 ), LFS lower (39% versus 70%; P < 10^-6 ) and OS lower than in the unrelated donor group (61% versus 74%; P = .005). By multivariate analysis, unrelated donor was superior to autologous transplantation for LFS (HR: 0.36, P < 10^-5) and OS (HR: 0.53, P = .01). ELN intermediate group 2: (52 autologous and 93 unrelated donors). The outcome was identical. We conclude that good risk patients get higher benefit from autologous transplantation. Intermediate risk 2 patients have the same outcome and Intermediate risk 1 patients get higher benefit from unrelated donor transplants.

Should patients with acute myeloid leukemia and measurable residual disease be transplanted in first complete remission?

PURPOSE OF REVIEW

Measurable ('minimal') residual disease in acute myeloid leukemia during first complete morphologic remission (MRD CR1) identifies patients with particularly high relapse risk and short survival. Here, we examine the evidence regarding optimal postremission treatment strategy for such patients.

RECENT FINDINGS

With chemotherapy alone or chemotherapy/autologous hematopoietic cell transplantation (HCT), disease recurrence appears inevitable in patients with MRD CR1. Nonrandomized studies indicate that allogeneic HCT improves outcomes over chemotherapy and/or autologous HCT, although relapse risks remain substantial. Emerging data suggest that myeloablative cord blood HCT may overcome the negative impact of MRD to a greater degree than other transplants, but the relative contributions of intensified conditioning and stem cell source to this effect are unknown.

SUMMARY

Available evidence supports the recommendation to consider allogeneic HCT for all acute myeloid leukemia patients in MRD CR1. Whether cord blood transplants should be prioritized deserves further investigation. To what degree outcomes of MRD CR1 patients could be improved by treatment intensification during induction, postremission therapy and/or before transplantation to revert the patient into an MRD state is currently unknown, as is the value of post-transplant preemptive therapies. These remain areas worthy of investigation, preferably in the setting of controlled clinical trials.

Autologous stem cell transplantation for adult acute myelocytic leukemia in first remission-Better outcomes after busulfan and melphalan compared with busulfan and cyclophosphamide: A retrospective study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

BACKGROUND

Autologous stem cell transplantation (ASCT) for adult acute myelogenous leukemia (AML) is a valid therapeutic option for patients with good-risk and intermediate-risk disease. The authors used the registry of the European Society for Blood and Marrow Transplantation to compare combined busulfan and melphalan (BUMEL) with combined busulfan and cyclophosphamide (BUCY) before transplantation.

METHODS

From 2005 to 2013, 853 patients with available cytogenetics underwent ASCT in first remission, including 257 after receiving BUMEL and 596 after receiving BUCY. The proportion of patients with good-risk AML was lower in those who received BUMEL (14% vs 20%; P = .02). More patients who received BUMEL underwent autograft in molecular remission (89% vs 78%; P = .02). Three years after transplantation, the relapse incidence (RI) was 48.7%, the leukemia-free survival (LFS) rate was 47.7%, the overall survival (OS) rate was 66.2%, and the nonrelapse mortality (NRM) rate was 3.6%.

RESULTS

Patients who underwent an autograft after receiving BUMEL fared better than those who underwent an autograft after receiving BUCY with a lower RI (39.5% vs 52.2%; hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.49-0.87; P = .003) a better LFS (55.4% vs 44.6%; HR, 0.69; 95% CI, 0.53-0.89; P = .005), and a better OS (73.8% vs 63%; HR, 0.62; 95% CI, 0.47-0.82; P = .0007). There was no difference in the NRM rate (BUMEL vs BUCY, 4.5% vs 3.2%, respectively). Among 74 patients in the BUMEL group and 187 in the BUCY group who underwent autograft in molecular remission, the RI was 30% versus 51%, respectively (univariate analysis; P = .01), and the LFS rate was 66% versus 47%, respectively (univariate analysis; P = .03).

CONCLUSIONS

In patients with AML in first complete remission who undergo ASCT, the BUMEL combination is a better preparative regimen. Cancer 2017;123:824-31. © 2016 American Cancer Society.

Multigene Measurable Residual Disease Assessment Improves Acute Myeloid Leukemia Relapse Risk Stratification in Autologous Hematopoietic Cell Transplantation

We report here the largest study to date of adult patients with acute myeloid leukemia (AML) tested for measurable residual disease (MRD) at the time of autologous hematopoietic cell transplantation (auto-HCT). Seventy-two adult patients who underwent transplantation between 2004 and 2013 at a single academic medical center (University of California San Francisco) were eligible for this retrospective study based on availability of cryopreserved granulocyte colony-stimulating factor (GCSF)-mobilized autologous peripheral blood progenitor cell (PBPC) leukapheresis specimens ("autografts"). Autograft MRD was assessed by molecular methods (real-time quantitative PCR [RQ-PCR] for Wilms tumor 1 (WT1) alone or a multigene panel) and by multiparameter flow cytometry (MPFC). WT1 RQ-PCR testing of the autograft had low sensitivity for relapse prediction (14%) and a negative predictive value of 51%. MPFC failed to identify MRD in any of 34 autografts tested. Combinations of molecular MRD assays, however, improved prediction of post-auto-HCT relapse. In multivariate analysis of clinical variables, including age, gender, race, cytogenetic risk category, and CD34⁺ cell dose, only autograft multigene MRD as assessed by RQ-PCR was statistically significantly associated with relapse. One year after transplantation, only 28% patients with detectable autograft MRD were relapse free, compared with 67% in the MRD-negative cohort. Multigene MRD, while an improvement on other methods tested, was however suboptimal for relapse prediction in unselected patients, with specificity of 83% and sensitivity of 46%. In patients with known chromosomal abnormalities or mutations, however, better predictive value was observed with no relapses observed in MRD-negative patients in the first year after auto-HCT compared with 83% incidence of relapse in the MRD-positive patients (hazard ratio, 12.45; P = .0016). In summary, increased personalization of MRD monitoring by use of a multigene panel improved the ability to risk stratify patients for post-auto-HCT relapse. WT1 RQ-PCR and flow cytometric assessment for AML MRD in autograft samples had limited value for predicting relapse after auto-HCT. We demonstrate that cryopreserved autograft material presents unique challenges for AML MRD testing because of the masking effects of previous GCSF exposure on gene expression and flow cytometry signatures. In the absence of information regarding diagnostic characteristics, sources other than GCSF-stimulated PBSC leukapheresis specimens should be considered as alternatives for MRD testing in AML patients undergoing auto-HCT.

Autologous stem cell transplantation versus alternative allogeneic donor transplants in adult acute leukemias

The availability of alternative sources of stem cells including most recently T-replete haploidentical marrow or peripheral blood, and the increasing use of reduced-intensity conditioning (RIC), renders feasible an allogeneic transplant to almost all patients with acute leukemia up to 70 years of age. Autologous stem cell transplantation (ASCT) for consolidation of complete remission (CR), however, offers in some circumstances an alternative option. Although associated with a higher relapse rate, autologous transplant benefits from a lower non-relapse mortality, the absence of graft-versus-host disease (GVHD), and a better quality of life for long-term survivors. The recent use of intravenous busulfan (IVBU) with high-dose melphalan, better monitoring of minimal residual disease (MRD), and maintenance therapy post autografting bring new interest. Few retrospective studies compared the outcome following alternative donor versus autologous transplants for remission consolidation. Genoidentical and phenoidentical allogeneic stem cell transplantations are undisputed gold standards, but there are no data showing the superiority of alternative allogeneic donor over autologous transplantation, at the time of undetectable MRD, in patients with good- and intermediate-1 risk acute myelocytic leukemia (AML) in first complete remission (CR1), acute promyelocytic leukemia in second complete remission (CR2), and Philadelphia chromosome-positive (Ph(+)) acute lymphocytic leukemia (ALL).

Immune responses to WT1 in patients with AML or MDS after chemotherapy and allogeneic stem cell transplantation

Wilms' tumor gene 1 (WT1) is overexpressed in leukemia and WT1-derived CD8(+) T-cell epitopes for immunotherapies targeting WT1 have been defined. Here, we analyzed expression of WT1 in 226 peripheral blood and bone marrow samples from patients with acute myeloid leukemia or myelodysplastic syndrome (AML/MDS) before and after allogeneic stem cell transplantation (SCT). Transcripts were assessed by quantitative polymerase chain reaction, and WT1-specific CD8+ cytotoxic T cells (CTL) were monitored by tetramer staining and enzyme-linked immunospot (ELISPOT) assays. Reduction of WT1 levels correlated with a longer survival (p < 0.01). Increment of WT1 transcripts eventually resulted in relapse and subsequent death of the patients. In patients with longer survival and continuous complete remission (cCR) after SCT, higher and enduring frequencies of WT1-specific CTL than in patients developing a relapse were detected. These cells were effector T cells secreting interferon gamma and granzyme B. In summary, WT1 is a suitable marker for the detection of minimal residual disease after SCT or chemotherapy. A rising WT1 signal correlated with a dismal prognosis of the patients. WT1-specific CD8(+) T cells might contribute to the maintenance of a cCR. Targeting WT-1 by peptide/protein vaccination as well as adoptive transfer of genetically modified T cells are future options in the individualized therapy for AML/MDS patients.

Autologous stem cell transplantation for adult acute leukemia in 2015: time to rethink? Present status and future prospects

The use of autologous stem cell transplantation (ASCT) as consolidation therapy for adult patients with acute leukemia has declined over time. However, multiple randomized studies in the past have reported lower relapse rates after autologous transplantation compared with chemotherapy and lower non-relapse mortality rates compared with allogeneic transplantation. In addition, quality of life of long-term survivors is better after autologous transplantation than after allogeneic transplantation. Further, recent developments may improve outcomes of autograft recipients. These include the use of IV busulfan and the busulfan+melphalan combination, better detection of minimal residual disease (MRD) with molecular biology techniques, the introduction of targeted therapies and post-transplant maintenance therapy. Therefore, ASCT may nowadays be reconsidered for consolidation in the following patients if and when they reach a MRD-negative status: good- and at least intermediate-1 risk acute myelocytic leukemia in first CR, acute promyelocytic leukemia in second CR, Ph-positive acute lymphocytic leukemia. Conversely, patients with MRD-positive status or high-risk leukemia should not be considered for consolidation with ASCT.

Indications for allo- and auto-SCT for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2015

This is the sixth special report that the European Society for Blood and Marrow Transplantation regularly publishes on the current practice and indications for haematopoietic SCT for haematological diseases, solid tumours and immune disorders in Europe. Major changes have occurred in the field of haematopoietic SCT over the last years. Cord blood units as well as haploidentical donors have been increasingly used as stem cell sources for allo-SCT, thus, augmenting the possibility of finding a suitable donor for a patient. Continuous refinement of conditioning strategies has also expanded not only the number of potential indications but also has permitted consideration of older patients or those with co-morbidity for a transplant. There is accumulating evidence of the role of haematopoietic SCT in non-haematological disorders such as autoimmune diseases. On the other hand, the advent of new drugs and very effective targeted therapy has challenged the role of SCT in some instances or at least, modified its position in the treatment armamentarium of a given patient. An updated report with revised tables and operating definitions is presented.

Imprinted genes in myeloid lineage commitment in normal and malignant hematopoiesis

Genomic imprinting is characterized by the parent-of-origin monoallelic expression of several diploid genes because of epigenetic regulation. Imprinted genes (IGs) are key factors in development, supporting the ability of a genotype to produce phenotypes in response to environmental stimuli. IGs are highly expressed during prenatal stages but are downregulated after birth. They also affect aspects of life other than growth such as cognition, behavior, adaption to novel environments, social dominance and memory consolidation. Deregulated genomic imprinting leads to developmental disorders and is associated with solid and blood cancer as well. Several data have been published highlighting the involvement of IGs in as early as the very small embryonic-like stem cells stage and further during myeloid lineage commitment in normal and malignant hematopoiesis. Therefore, we have assembled the current knowledge on the topic, based mainly on recent findings, trying not to focus on a particular cluster but rather to have a global view of several different IGs in hematopoiesis.