A novel pyroptosis-related gene signature exhibits distinct immune cells infiltration landscape in Wilms' tumor.

BACKGROUND: Wilms' tumor (WT) is the most common renal tumor in childhood. Pyroptosis, a type of inflammation-characterized and immune-related programmed cell death, has been extensively studied in multiple tumors. In the current study, we aim to construct a pyroptosis-related gene signature for predicting the prognosis of Wilms' tumor. METHODS: We acquired RNA-seq data from TARGET kidney tumor projects for constructing a gene signature, and snRNA-seq data from GEO database for validating signature-constructing genes. Pyroptosis-related genes (PRGs) were collected from three online databases. We constructed the gene signature by Lasso Cox regression and then established a nomogram. Underlying mechanisms by which gene signature is related to overall survival states of patients were explored by immune cell infiltration analysis, differential expression analysis, and functional enrichment analysis. RESULTS: A pyroptosis-related gene signature was constructed with 14 PRGs, which has a moderate to high predicting capacity with 1-, 3-, and 5-year area under the curve (AUC) values of 0.78, 0.80, and 0.83, respectively. A prognosis-predicting nomogram was established by gender, stage, and risk score. Tumor-infiltrating immune cells were quantified by seven algorithms, and the expression of CD8( +) T cells, B cells, Th2 cells, dendritic cells, and type 2 macrophages are positively or negatively correlated with risk score. Two single nuclear RNA-seq samples of different histology were harnessed for validation. The distribution of signature genes was identified in various cell types. CONCLUSIONS: We have established a pyroptosis-related 14-gene signature in WT. Moreover, the inherent roles of immune cells (CD8( +) T cells, B cells, Th2 cells, dendritic cells, and type 2 macrophages), functions of differentially expressed genes (tissue/organ development and intercellular communication), and status of signaling pathways (proteoglycans in cancer, signaling pathways regulating pluripotent of stem cells, and Wnt signaling pathway) have been elucidated, which might be employed as therapeutic targets in the future.

Gene expression-based immune infiltration analyses of renal cancer and their associations with survival outcome.

BACKGROUND: Renal cancer is a common malignant tumor with an increasing incidence rate. METHODS: In this study, based on the gene expression profiles, we analyzed the compositions of tumor-infiltrating immune cells (TIICs) in renal cancer and paracancerous samples using CIBERSORT. The proportions of 22 TIICs subsets in 122 paired renal carcinoma and paracancerous samples, and 224 Wilms tumor (WT) samples varied between intragroup and intergroup. RESULTS: After analyzed the difference of TIICs composition between renal cancer and paired paracancerous samples, we found that M0 macrophages and CD8 T cells were significantly elevated, while naive B cells were significantly decreased in renal cancer samples compared with paracancerous samples. Survival analysis showed that high overall TIICs proportion, the low proportion of resting mast cells and the high proportion of activated memory CD4 T cells were associated with poor prognosis of renal cancer patients. In addition, 3 clusters were identified by hierarchical clustering analysis, and they presented a distinct prognosis. Cluster 1 had superior survival outcomes, while cluster 2 had an inferior survival outcome. CONCLUSIONS: Our study indicated that overall TIICs proportion, certain TIICs subset proportion, including resting mast cells and activated memory CD4 T cells, and distinct cluster patterns were associated with the prognosis of renal cancer, which was significant for the clinical surveillance and treatment of renal cancer.

Adaptive from Innate: Human IFN-γ+CD4+ T Cells Can Arise Directly from CXCL8-Producing Recent Thymic Emigrants in Babies and Adults.

We recently demonstrated that the major effector function of neonatal CD4+ T cells is to produce CXCL8, a prototypic cytokine of innate immune cells. In this article, we show that CXCL8 expression, prior to proliferation, is common in newly arising T cells (so-called "recent thymic emigrants") in adults, as well as in babies. This effector potential is acquired in the human thymus, prior to TCR signaling, but rather than describing end-stage differentiation, such cells, whether isolated from neonates or adults, can further differentiate into IFN-γ-producing CD4+ T cells. Thus, the temporal transition of host defense from innate to adaptive immunity is unexpectedly mirrored at the cellular level by the capacity of human innate-like CXCL8-producing CD4+ T cells to transition directly into Th1 cells.

The Antitumor Activity of TCR-Mimic Antibody-Drug Conjugates (TCRm-ADCs) Targeting the Intracellular Wilms Tumor 1 (WT1) Oncoprotein.

Wilms tumor 1 (WT1) oncoprotein is an intracellular oncogenic transcription factor which is barely expressed in normal adult tissues but over expressed in a variety of leukemias and solid cancers. WT1-derived HLA-A*02:01 T cell epitope, RMFPNAPYL (RMF), is a validated target for T cell-based immunotherapy. We generated two T cell receptor mimic antibody-drug conjugates (TCRm-ADCs), ESK-MMAE, and Q2L-MMAE, against WT1 RMF/HLA-A*02:01 complex with distinct affinities, which mediate specific antitumor activity. Although ESK-MMAE showed higher tumor growth inhibition ratio in vivo, the efficacy of them was not so promising, which might be due to low expression of peptide/HLA targets. Therefore, we explored a bispecific TCRm-ADC that exerted more potent tumor cytotoxicity compared with TCRm-ADCs. Hence, our findings validate the feasibility of the presenting intracellular peptides as the targets of ADCs, which broadens the antigen selection range of antibody-based drugs and provides new strategies for precision medicine in tumor therapy.

[Expression of regulatory T cells and natural killer T cells in peripheral blood of children with Wilms tumor].

OBJECTIVE: To study the changes and clinical significance of CD4+CD25+CD127low regulatory T cells (Treg) and CD3+CD16+CD56+ natural killer T cells (NKT) in peripheral blood of children with Wilms tumor. METHODS: Twenty-one children with Wilms tumor were enrolled as the case group, and twenty-one healthy children for physical examinations were enrolled as the control group. Flow cytometry was used to detect the levels of CD4+CD25+CD127low T cells and CD3+CD16+CD56+ T cells in peripheral blood of two groups. RESULTS: The level of Treg cells in peripheral blood of the case group was significantly lower than in the control group (p<0.05). The level of NKT cells in peripheral blood of the case group was significantly higher than in the control group (p<0.05). CONCLUSIONS: Treg cells and NKT cells play important roles in the occurrence and development of Wilms tumor. Treg cells and NKT cells may be useful indexes for evaluating immunological function in children with Wilms tumor.

Secondary Hemophagocytic Lymphohistiocytosis in a Patient With Favorable Histology Wilms Tumor.

Secondary hemophagocytic lymphohistiocytosis (HLH) is most commonly associated with malignancy, infection, or an underlying autoimmune disorder. Malignancy-associated hemophagocytic syndrome is responsible for most secondary HLH cases, but it has not been well described in children. We present a case of a 4-year-old female with favorable histology of Wilms tumor who developed secondary HLH after unsuccessful resection of the tumor and initiation of chemotherapy.

Orthotopic Wilms tumor xenografts derived from cell lines reflect limited aspects of tumor morphology and clinical characteristics.

BACKGROUND: Wilms tumor (WT) is a pediatric tumor of the kidney, the treatment of which includes heavy chemotherapy. Affected children would likely benefit from more targeted therapies with limited side effects. Establishment of relevant orthotopic WT xenografts is important to better understand mechanisms of WT growth and for preclinical drug testing. PROCEDURE: Here we established and characterized orthotopic xenografts from WT cell lines WiT49, CCG-99-11, and WT-CLS1 to ascertain in what aspects each of them recapitulated WT histology, immunophenotype, invasion, and metastatic spread. RESULTS: WiT49 xenografts recapitulated near triphasic WTs with clear WT1 staining and anaplastic features, but with tumor restricted to the kidney. On the contrary both CCG-99-11 and WT-CLS1 xenografts conveyed metastatic disease. CCG-99-11 showed a blastemal phenotype whereas WT-CLS1 xenografts did not properly reflect any specific WT subtype. CONCLUSIONS: From the three tested cell lines, orthotopic WiT49 xenografts best reflect the triphasic pattern of classical WT.

Worse Wilms' Tumor Outcomes Associated With Chemical Complementarity for Multiple T-Cell Receptor CDR3-CMV Epitope Pairs.

BACKGROUND/AIM: Wilms' tumors are pediatric renal tumors that generally have a good prognosis and outcomes. Viral illnesses have been linked to development of neoplasms and should be considered as a factor that could modulate overall survival. MATERIALS AND METHODS: We considered recently developed adaptive immune receptor, genomics and bioinformatics approaches to assess the potential impact of cytomegalovirus (CMV) infections in Wilms' tumor. RESULTS: T-cell receptor (TCR) complementarity determining region-3 (CDR3) amino acid sequences from Wilms' tumor specimens represented by the Therapeutically Applicable Research to Generate Effective Treatments dataset were compared with known anti-CMV TCR CDR3s, indicating that cases representing the anti-CMV TCR CDR3s had worse outcomes. Then, a chemical complementarity scoring approach for the Wilms' tumor, TCR CDR3s and a series of CMV antigens further indicated that cases representing a higher chemical complementarity to the CMV antigens had worse outcomes. CONCLUSION: Overall, we present a potentially novel method to assess CMV infections and identify patients who could benefit from therapies that address such infections.

Specificity for the tumor-associated self-antigen WT1 drives the development of fully functional memory T cells in the absence of vaccination.

Recently, vaccines against the Wilms Tumor antigen 1 (WT1) have been tested in cancer patients. However, it is currently not known whether physiologic levels of WT1 expression in stem and progenitor cells of normal tissue result in the deletion or tolerance induction of WT1-specific T cells. Here, we used an human leukocyte antigen-transgenic murine model to study the fate of human leukocyte antigen class-I restricted, WT1-specific T cells in the thymus and in the periphery. Thymocytes expressing a WT1-specific T-cell receptor derived from high avidity human CD8 T cells were positively selected into the single-positive CD8 population. In the periphery, T cells specific for the WT1 antigen differentiated into CD44-high memory phenotype cells, whereas T cells specific for a non-self-viral antigen retained a CD44(low) naive phenotype. Only the WT1-specific T cells, but not the virus-specific T cells, displayed rapid antigen-specific effector function without prior vaccination. Despite long-term persistence of WT1-specific memory T cells, the animals did not develop autoimmunity, and the function of hematopoietic stem and progenitor cells was unimpaired. This is the first demonstration that specificity for a tumor-associated self-antigen may drive differentiation of functionally competent memory T cells.

Multicenter study identified molecular blood-born protein signatures for Wilms Tumor.

Wilms Tumor (WT) is the most common renal childhood tumor. Recently, we reported a cDNA microarray expression pattern that varied between WTs with different risk histology. Since the Societé Internationale d'Oncologie Pédiatrique (SIOP) in Europe initiates treatment without a histological confirmation, it is important to identify blood-born markers that indicate WT development. In a multicenter study, we established an autoantibody signature by using an array with 1,827 recombinant E. coli clones. This array was screened with sera of patients with WT recruited by SIOP or the Children's Oncology Group (COG). We report an extended number of antigens that are reactive with autoantibodies present in sera from patients with WT. We established an autoantibody signature that separates untreated patients with WT recruited in SIOP from non-WT controls with a specificity of 0.83 and a sensitivity of 0.82 at standard deviations of 0.02 and 0.04, respectively. Likewise, patients recruited in the COG in the United States were separated from the controls with an accuracy of 0.83 at a standard deviation of 0.02. Proteins that were most significant include zinc finger proteins (e.g., ZFP 346), ribosomal proteins and the protein fascin that has been associated with various types of cancer including renal cell carcinoma. Our study provides first evidence for autoantibody signatures for WTs and suggests that these may be most informative before chemotherapy. We present the first multicenter study of autoantibody signatures in patients with WT. We established an autoantibody signature that separates patients with WT from controls.

[WT1-targeting cancer vaccine].

Wilms' tumor gene WT1 encodes a transcription factor and functions as an oncogene. WT1 gene product WT1 protein is a promising par-tumor-associated antigen. WT1 peptide-based immunotherapy has been performing for more than six hundred patients with leukemias and various types of solid tumors. This immunotherapy is safe and has clinical benefit especially for leukemia, glioblastoma multiforme, advanced pancreatic cancer, and ovarian cancer. As a new strategy for cancer treatment, it should be recommended to initiate immunotherapy that had a potential of eradication of cancer stem cells before surgery, chemo- and radio-therapy.

EV PD-L1 Contributes to Immunosuppressive CD8+ T Cells in Peripheral Blood of Pediatric Wilms Tumor.

Wilms tumor (WT) is the most common renal cancer and the most prevalent abdominal cancer in children. Children with recurrent or progressive forms of WT could benefit from novel immune-targeted approaches. While the immune status of these patients, especially the immunosuppression of peripheral T cells, was rarely reported. The present study enrolled a consecutive series of 14 Chinese WT children and 14 age- and gender-matched healthy controls. We demonstrated that plasma extracellular vesicular (EV) PD-L1 levels significantly increased in WT patients than in healthy controls. EV PD-L1 significantly inhibited the activation of human CD8+ T cells by down-regulating the cell surface CD69 expression and the intracellular IFNγ and TNFα production in vitro. In peripheral CD8+ T cells of WT patients, the intracellular IFNγ and TNFα production significantly decreased than healthy controls. The level of plasma EV PD-L1 significantly correlated with the intracellular TNFα production in peripheral CD8+ T cells of WT patients. In conclusion, the significantly increased plasma EV PD-L1 in WT patients contributed to the immunosuppression of peripheral CD8+ T cells. Monitoring the level of plasma EV PD-L1 will be helpful for the selection of immune-targeted therapies for WT patients.

Immune checkpoint inhibitors in Wilms' tumor and Neuroblastoma: What now?

BACKGROUND: Therapeutic activation of tumor-infiltrating lymphocytes using monoclonal antibodies targeting PD1 or PD-L1 (immune checkpoint inhibitors-ICIs) has revolutionized treatment of specific solid tumors in adult cancer patients, and much hope has been placed on a similar effect in relapsed or refractory solid pediatric tumors. Recent clinical trials have disappointingly shown an almost nonexistent response rate, while case reports have demonstrated that some pediatric patients do achieve durable responses when treated with this type of drug. AIM: To elucidate this paradox, we mapped the landscape of expressed neoantigens as well as the levels of immune cell infiltration in the two most common extracranial solid pediatric tumors: Wilms tumor and neuroblastoma using state-of-the-art in silico analysis of a large cohort of patients with these tumors. METHODS: By integration of whole exome sequencing and RNA-sequencing, we mapped the landscape of neoantigens in the TARGET cohorts for these diagnoses and correlated these findings with known genetic prognostic markers. RESULTS: Our analysis shows that these tumors typically have much lower levels of expressed neoantigens than commonly seen in adult cancers, but we also identify subgroups with significantly higher levels of neoantigens. For neuroblastomas, the cases with higher levels of neoantigens were confined to the group without MYCN-amplification and for Wilms tumor restricted to the TP53-mutated cases. Furthermore, we demonstrate that neuroblastomas have an unexpectedly high level of CD8+ tumor-infiltrating lymphocytes, even when compared to adult tumor types where ICI is an approved treatment. CONCLUSION: These results could be important to consider when designing future clinical trials of ICI treatment in pediatric patients with relapsed or refractory solid tumors.

Mutation or loss of Wilms' tumor gene 1 (WT1) are not major reasons for immune escape in patients with AML receiving WT1 peptide vaccination.

BACKGROUND: Efficacy of cancer vaccines may be limited due to immune escape mechanisms like loss or mutation of target antigens. Here, we analyzed 10 HLA-A2 positive patients with acute myeloid leukemia (AML) for loss or mutations of the WT1 epitope or epitope flanking sequences that may abolish proper T cell recognition or epitope presentation. METHODS: All patients had been enrolled in a WT1 peptide phase II vaccination trial (NCT00153582) and ultimately progressed despite induction of a WT1 specific T cell response. Blood and bone marrow samples prior to vaccination and during progression were analyzed for mRNA expression level of WT1. Base exchanges within the epitope sequence or flanking regions (10 amino acids N- and C-terminal of the epitope) were assessed with melting point analysis and sequencing. HLA class I expression and WT1 protein expression was analyzed by flow cytometry. RESULTS: Only in one patient, downregulation of WT1 mRNA by 1 log and loss of WT1 detection on protein level at time of disease progression was observed. No mutation leading to a base exchange within the epitope sequence or epitope flanking sequences could be detected in any patient. Further, no loss of HLA class I expression on leukemic blasts was observed. CONCLUSION: Defects in antigen presentation caused by loss or mutation of WT1 or downregulation of HLA molecules are not the major basis for escape from the immune response induced by WT1 peptide vaccination.

Development of a Wilms' tumor antigen-specific T-cell receptor for clinical trials: engineered patient's T cells can eliminate autologous leukemia blasts in NOD/SCID mice.

BACKGROUND: The Wilms' tumor antigen (WT1) is an attractive target for immunotherapy of leukemia. In the past, we isolated and characterized the specificity and function of a WT1-specific T-cell receptor. The goal of this translational study was to develop a safe and efficient WT1-T-cell receptor retroviral vector for an adoptive immunotherapy trial with engineered T cells. DESIGN AND METHODS: We generated a panel of retroviral constructs containing unmodified or codon-optimized WT1-T-cell receptor alpha and beta genes, linked via internal ribosome entry sites or 2A sequences, with or without an additional inter-chain disulfide bond in the T-cell receptor constant domains. These constructs were functionally analyzed in vitro, and the best one was tested in an autologous primary leukemia model in vivo. RESULTS: We identified a WT1-T-cell receptor construct that showed optimal tetramer staining, antigen-specific cytokine production and killing activity when introduced into primary human T cells. Fresh CD34(+) cells purified from a patient with leukemia were engrafted into NOD/SCID mice, followed by adoptive immunotherapy with patient's autologous T cells transduced with the WT1-T-cell receptor. This therapeutic treatment evidently decreased leukemia engraftment in mice and resulted in a substantial improvement of leukemia-free survival. CONCLUSIONS: This is the first report that patient's T cells, engineered to express the WT1-T-cell receptor, can eliminate autologous leukemia progenitor cells in an in vivo model. This study provides a firm basis for the planned WT1-T-cell receptor gene therapy trial in leukemia patients.

Impact of mature dendritic cells pulsed with a novel WT1 helper peptide on the induction of HLA­A2­restricted WT1­reactive CD8+ T cells.

The proliferation and activation of CD4+ T helper 1 (Th1) cells and CD8+ cytotoxic T lymphocytes (CTLs) that produce interferon­Î³ (IFN­Î³) is an essential action of effective cancer vaccines. Recently, a novel Wilms' tumor 1 (WT1) helper peptide (WT1 HP34­51; amino acid sequence, WAPVLDFAPPGASAYGSL) applicable for various human leukocyte antigen (HLA) subtypes (HLA­DR, HLA­DP and HLA­DQ) was reported to increase peptide immunogenicity; however, the function of WT1 HP34­51 remains unclear. In the present study, mature dendritic cells (mDCs) pulsed with WT1 HP34­51 (mDC/WT1 HP34­51) activated not only WT1­specific CD4+ T cells but also CD8+ T cells that produced IFN­Î³ following stimulation with immature dendritic cells (imDCs) pulsed with WT1 killer peptide (imDC/WT1 KP37­45) in an HLA­A*02:01­ or HLA­A*02:06­restricted manner. Furthermore, the activated WT1­reactive CD4+ Th1 cells were predominantly effector memory (EM) T cells. In 5 of 12 (41.7%) patients with cancer carrying the HLA­A*02:01 or HLA­A*02:06 allele, WT1­reactive CD8+ T cells stimulated with mDC/WT1 HP34­51 enhanced their levels of WT1 KP37­45­specific IFN­Î³ production, with an increase >10%. Simultaneous activation of CD4+ and CD8+ T cells occurred more often when stimulation with mDC/WT1 HP34­51 was combined with imDC/WT1 KP37­45 restimulation. These results indicated that the novel mDC/WT1 HP34­51 combination induced responses by WT1­specific EM CD4+ Th1 cells and HLA­A*02:01­ or HLA­A*02:06­restricted CD8+ CTLs, suggesting its potential as a WT1­targeting cancer vaccine.

Changes of blood count, lymphocyte subpopulations and immunoglobulin levels in nephroblastoma long term survivors.

The aim of this study was to investigate the frequency of blood count, lymphocyte subpopulations, and immunoglobulin levels alterations in a group of healthy nephroblastoma long-term survivors. The group included 122 nephroblastoma longterm survivors who were at least five years post anticancer therapy and free of any sign of recurrence The proportion of lymphocyte subpopulations was analyzed by flow cytometry using antibodies anti CD45 FITC/CD14 PE, anti CD3 FITC/ CD16+CD56 PE, anti CD4 FITC/ CD8 PE and anti CD20 FITC. Immunoglobulin G, A, and M levels were evaluated by immunoturbidimetry. Total blood count was also examined. The occurrence of decreased immunoglobulin levels, leukocytes, lymphocytes, and granulocytes count, proportion of T lymphocytes and their CD4+ subpopulation are not frequent. The most frequently decreased lymphocyte subpopulation was CD8 (15.5%). The most frequent abnormal findings were increased proportion of NK cells (38.5 %), B lymphocytes (38,52 %), decreased number of erythrocytes (25.2 %), hemoglobin levels (41.7 %) and hematocrit (13.9 %). The only significant differences between results of immunological examination and course of the disease were more frequently decreased proportion of CD4+ lymphocytes in recurrent disease survivors and lower IgA levels in survivors after radiotherapy. We found decreased at least one immunological parameter in one fifth of the survivors. The most frequently altered parameter was hemoglobin, which was decreased in 41.7 % of survivors. Decraesed hemoglobin may worsen quality of survivors life. Key words: nephroblastoma long-term survivors, blood count, lymphocyte subpopulations, immunoglobulin G, A, M serum levels.

Immune expression in children with Wilms tumor: a pilot study.

BACKGROUND: Given improvements in multimodality therapy, survival among children with Wilms tumor (WT) exceeds 90%. However, 15% of children with favorable histology and 50% of children with anaplastic WT experience recurrence or progression. Of patients with advanced disease, only 50% survive to adulthood. In adult malignancies (including renal tumors), patient survival has improved with the advent of immunotherapy. However, little is known about the immune microenvironment of WT, making the potential role of immunotherapy unclear. OBJECTIVE: The objective of the study is to perform an exploratory, descriptive analysis of the immune milieu in WT. STUDY DESIGN: Between 2016 and 2017, all pediatric patients with WT, some of whom received neoadjuvant chemotherapy, underwent ex vivo wedge biopsy at the time of nephrectomy. The fresh tumor tissue and peripheral blood samples were analyzed for infiltrating immune infiltrate and effector cells using flow cytometry. Immunohistochemistry was performed for CD4, CD8, and PD-L1 expression. Matched blood samples were obtained for each patient, and circulating immune cells were analyzed by flow cytometry. RESULTS: A total of six patients were enrolled. One patient with neuroblastoma was excluded. The remaining five patients included the following: two with unilateral WT (resected before chemotherapy), two with bilateral WT (resected after neoadjuvant chemotherapy), and one with Denys-Drash syndrome, end-stage renal disease, and history of WT in the contralateral kidney. Immune analysis showed that WT were infiltrated by immune cells regardless of chemotherapy status. CD8 and CD4 T cells were present in the tumor tissue and exhibited an activated phenotype. Elevated levels of natural killer (NK) cells were observed in the tumors (Figure). Immune checkpoint PD-L1 was also found expressed in one of the tumors stained. DISCUSSION: In this pilot study, it was found that WTs were infiltrated by immune cells (CD45+) both before and after chemotherapy. Elevated levels of NK cells infiltrating the tumor specimens, which were quantitatively increased compared with levels of NK cells circulating in the blood, were noted. T cells, particularly CD4+ and CD8+ T cells, were present in tumor specimens. Tumor-infiltrating CD4 and CD8 T cells displayed an activated phenotype as defined by increased expression of human leukocyte antigen-DR isotype (HLA-DR), programmed cell death protein 1 (PD1), and CD57. Together, these findings suggest that WT microenvironment is immune engaged and may be susceptible to immunotherapy similar to other malignancies. CONCLUSIONS: These pilot data suggest an immune-engaged tumor microenvironment is present within WT. This implies that WT may be susceptible to immunotherapy similar to adult renal tumors and other adult malignancies. Follow-up studies are currently underway.

Peptide vaccines for myeloid leukaemias.

The development of cancer vaccines directed against myeloid leukaemias has been a research area of intense interest in the past decade. Both human studies in vitro and mouse models in vivo have demonstrated that leukaemia-associated antigens (LAAs), such as the fusion protein BCR-ABL, Wilms' tumour protein and proteinase 3, may serve as effective targets for cellular immunotherapy. Peptide-based vaccines are able to induce cytotoxic T-lymphocyte responses that kill leukaemia cells. Based on these results, pilot clinical trials have been initiated in chronic and acute myeloid leukaemia and other haematological malignancies, which include vaccination of patients with synthetic peptides derived from these LAAs. Results from these trials show that peptide vaccines are able to induce immune responses that are sometimes associated with clinical benefit. These early clinical results are promising and provide valuable information for future improvement of the vaccines. This chapter will focus mainly on discussing the preclinical studies of peptide vaccines in human systems, the results from clinical trials and the future prospects for vaccine therapy for myeloid leukaemia.