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Acute lymphoblastic leukemia type B (B-ALL) is the most common kind of pediatric leukemia, characterized by the clonal proliferation of type B lymphoid stem cells. Important progress in ALL treatments led to improvements in long-term survival; nevertheless, many adverse long-term consequences still concern the medical community. Molecular and cellular target therapies, together with immunotherapy, are promising strategies to overcome these concerns. Cannabinoids, enzymes involved in their metabolism, and cannabinoid receptors type 1 (CB1) and type 2 (CB2) constitute the endocannabinoid system, involved in inflammation, immune response, and cancer. CB2 receptor stimulation exerts anti-proliferative and anti-invasive effects in many tumors. In this study, we evaluated the effects of CB2 stimulation on B-ALL cell lines, SUP-B15, by RNA sequencing, Western blotting, and ELISA. We observe a lower expression of CB2 in SUP-B15 cells compared to lymphocytes from healthy subjects, hypothesizing its involvement in B-ALL pathogenesis. CB2 stimulation reduces the expression of CD9, SEC61G, TBX21, and TMSB4X genes involved in tumor growth and progression, and also negatively affects downstream intracellular pathways. Our findings suggest an antitumor role of CB2 stimulation in B-ALL, and highlight a functional correlation between CB2 receptors and specific anti-tumoral pathways, even though further investigations are needed.

Background: Osteosarcoma is an aggressive bone tumor. Itrepresents the principal cause of cancer-associated death in children.Considering the recent findings on the role of iron in cancer, iron chelation has been investigated for its antineoplastic properties in many tumors. Deferasirox is the most used iron chelator compound and in previous studies showed an anticancer effectinhematologic and solid malignancies. Eltrombopag is a Thrombopoietin receptor used in thrombocytopenia, that also binds and mobilize iron. It demonstrated an effect in iron overload conditions and also in contrasting cancer cells proliferation. Objective: We analyzed the effects of Deferasirox and Eltrombopag in Human Osteosarcoma cells, in the attempt to identify other therapeutic approaches for this tumor. Methods: We cultured and treated withDeferasirox and Eltrombopag, alone and in combination, two human osteosarcoma cell lines, MG63 and 143B. After 72h exposure, we performed RTqPCR, Western Blotting, Iron Assay and cytofluorimetric assays to evaluate the effect on viability, apoptosis, cell cycle progression and ROS production. Results: The iron chelating properties of the two compounds are confirmed also in Osteosarcoma, but we did not observe any direct effect on tumor progression. Discussion: We tested Deferasirox and Eltrombopag, alone and in combination, in Human Osteosarcoma cells for the first time and demonstrated that their iron chelating activity does not influence biochemical pathways related to cancer progression and maintenance. Conclusion: Although further investigations on possible effects mediated by cells of the tumor microenvironment could be of great interest, in vitro iron chelation in Osteosarcoma does not impair tumor progression.

Osteosarcoma is an aggressive bone tumor of the pediatric age. It is therefore important to improve conventional therapies (chemotherapy and surgery). Anticancer drugs often cause osteoporosis due to a misbalance of RANK/RANK-L/OPG pathway. Denosumab is a monoclonal antibody with high affinity and specificity to RANK-L, the ligand released by osteoblasts that enhances osteoclasts differentiation and bone resorption. It is used in osteoporosis and in other conditions characterized by bone mass loss. Doxorubicin is a chemotherapic drug used in several kinds of tumors, and also patients treated with it often develop osteoporosis. We investigated the effects of Denosumab alone and in combination with Doxorubicin, in two human osteosarcoma cell lines (MG63 and U-2 OS). We evaluated the effect of these treatments on apoptosis, cell cycle progression, invasion capacity and bone metabolism. We observed for the first time an anti-invasive effect of Denosumab in OS cells and confirmed its anti-osteoporotic activity also in Osteosarcoma. On the other hand, we demonstrate that Denosumab not only does not affect apoptosis and cell cycle progression, but when used in combination with Doxorubicin, it causes an unexpected reduction of its activity. These results indicate that the presence of Denosumab might inhibit the efficacy of the chemotherapic drug. In conclusion, while our results certainly support and confirm the efficacy of Denosumab in Osteoporosis, we discourage the use of Denosumab in addition to conventional chemotherapy in Osteosarcoma, even though, certainly further investigations are necessary to better clarify the clinical role of this monoclonal antibody in cancer.

The authors describe a newborn diagnosed with localized neuroblastoma that evolved to stage 4s at the age of 5 months. Peculiar features of the case included a bilateral adrenal primary, the skin as the only metastatic site, and the development of a muscular lesion late in the clinical course. The patient underwent left adrenalectomy and all other lesions regressed without further therapy. The case prompted a search for similar cases both in the Italian Neuroblastoma Registry and in the literature. All patients identified, although variously treated, survived with the exception of the 2 with MYCN gene amplification. We conclude that infants with neuroblastoma who undergo a transition from a localized to stage 4s disease could be less rare than expected. In the absence of unfavorable biology, a wait-and-see policy with strict follow-up could be adopted for these patients, avoiding potentially damaging systemic therapy.

Actually, there is still no consensus related to diagnostic and management algorithms in case of head and neck lymphadenopathy in children. The aim of our study was to analyze the causes of head and neck lymphadenopathy in children to determine a systematic diagnostic approach. We enrolled all cases of head and neck lymphadenopathy in children under the age of 18 diagnosed at the Unit of Hemato-Oncology, Pediatric Department of University "Luigi Vanvitelli," Naples, over a 15-year period (January 2003-December 2017). In total, 405 patients (271 males) were enrolled in the study. Thirteen cases due to other causes, were left off the study. Therefore, the study was performed on 392 cases. A total of 220 patients (56.1%) had a history of infection, 66 cases (16.8%) a diagnosis of neoplasia, and 101 (24.9%) cases a diagnosis of reactive inflammatory changes of nonspecific origin. We have observed the following from our study: (1) the acute infections are the most common causes of head and neck lymphadenopathy in the pediatric population; (2) in about a quarter of patients, the lymphadenopathy resulted by nonspecific origin; (3) the supraclavicular nodes should be regarded with a high index of suspicion of malignancy.

The improvement of chemotherapy, radiotherapy, and surgical interventions, together with hematopoietic stem cell transplantation, increased childhood cancer survival rate in the last decades, reaching 80% in Europe. Nevertheless, anti-cancer treatments are mainly responsible for the onset of long-term side effects in childhood cancer survivors (CCS), including alterations of the endocrine system function and activity. In particular, the most frequent dysfunction in CCS is a metabolic bone disorder characterized by low bone mineral density (BMD) with increased skeletal fragility. BMD loss is also a consequence of a sedentary lifestyle, malnutrition, and cancer itself could affect BMD, thus inducing osteopenia and osteoporosis. In this paper, we provide an overview of possible causes of bone impairment in CCS in order to propose management strategies for early identification and treatment of skeletal fragility in this population.

Background Among factors influencing the higher risk of developing unknown or rare adverse drug reactions (ADRs) among children and adolescents, there is the frequent off-label use of drugs that seems to be very common in pediatric oncological patients. Our study aim to collect and evaluate data on the safety profile of antineoplastic drugs and their off-label use in the pediatrics population using real life data. Methods We retrieved Individual Case Safety Reports (ICSRs) with an anticancer agent as suspected drug among those reported through the Campania spontaneous reporting system from 1 January 2013 to 30 September 2019. We classified ICSRs into four off-label categories: “age,” “route of administration,” “weight,” and “therapeutic indication.” We defined an ICSR as an off-label case if it met at least one of the aforementioned categories for at least one of the reported suspected antineoplastic drugs. Results A total of 18 ICSRs (7.6%) out of 236 were classified as off-label cases. The median age of patients was 13 years (interquartile range, IQR: 6–16), with 94.4% of cases occurring in male patients. In the classification of the off-label category, 16 ICSRs were categorized according to the “therapeutic indication” and two for the “age.” No case was categorized for the off-label categories “route of administration” and “weight.” The two off-label cases categorized as “age” were both related to the use of brentuximab vedotin for Hodgkin’s lymphoma in patients aged 16 years. Twenty-nine ADRs (1.6 suspected adverse drug reactions per ICSR) were identified among off-label cases. Among ADRs, those reported more than one were diarrhea (N = 3), neutropenia (N = 3), nausea (N = 2), pyrexia (N = 2), and vomit (N = 2). Conclusions Our findings showed a low number of ICSRs classified as off-label. The majority of off-label ICSRs were categorized for the “therapeutic indication.” This low number of off-label ICSRs might be largely due to the underreporting phenomenon, which is a major limit in pharmacovigilance. Therefore, we believe that spreading pharmacovigilance knowledge and awareness might improve this aspect.

Osteosarcoma is the most common primary malignant tumor of bone in children and adolescents. Bortezomib (BTZ) is an approved anticancer drug, classified as a selective reversible inhibitor of the ubiquitin-dependent proteasome system, that leads to cancer cell cycle arrest and apoptosis reducing the invasion ability of Osteosarcoma cells in vitro. It also regulates the RANK/RANKL/OPG system, involved in the pathogenesis of bone tumors and in cell migration. A side effect of BTZ is to induce painful sensory peripheral neuropathy which lead to cessation of therapy or dose reduction. Recently BTZ has been evaluated in combination with Cannabinoids targeting CB1 receptor, demonstrating a promising synergic effect. The Endocannabinoid/Endovanilloid (EC/EV) system includes two G protein-coupled receptors (CB1 and CB2), the Transient Potential Vanilloid 1 (TRPV1) channel and their endogenous ligands and enzymes. CB1 and CB2 are expressed mainly in Central Nervous System and Immune Peripheral cells respectively. TRPV1 is also expressed in primary sensory neurons and is involved in pain modulation. EC/EV system induces apoptosis, reduces invasion and cell proliferation in Osteosarcoma cell lines and is involved in bone metabolism. We analyzed the effects of BTZ, alone and in combination with selective agonists at CB2 (JWH-133) and TRPV1 (RTX) receptors, in the Osteosarcoma cell line (HOS) on Apoptosis, Cell Cycle progression, migration and bone balance. We observed that the stimulation of CB2 and TRPV1 receptors increase the efficacy of BTZ in inducing apoptosis and reducing invasion, cell cycle progression and by modulating bone balance. These data suggest the possibility to use BTZ, in combination with EC/EV agonists, in Osteosarcoma therapy reducing its dose and its side effects.

T-Acute Lymphoblastic Leukemia (T-ALL) is less frequent than B-ALL, but it has poorer outcome. For this reason new therapeutic approaches are needed to treat this malignancy. The Endocannabinoid/Endovanilloid (EC/EV) system has been proposed as possible target to treat several malignancies, including lymphoblastic diseases. The EC/EV system is composed of two G-Protein Coupled Receptors (CB1 and CB2), the Transient Potential Vanilloid 1 (TRPV1) channel, their endogenous and exogenous ligands and enzymes. CB1 is expressed mainly in central nervous system while CB2 predominantly on immune and peripheral cells, therefore we chose to selectively stimulate CB2 and TRPV1. We treated T-ALL lymphoblasts derived from 4 patients and Jurkat cells with a selective agonist at CB2 receptor: JWH-133 [100 nM] and an agonist at TRPV1 calcium channel: RTX [5 uM] at 6, 12 and 24 hours. We analyzed the effect on apoptosis and Cell Cycle Progression by a cytofluorimetric assays and evaluated the expression level of several target genes (Caspase 3, Bax, Bcl-2, AKT, ERK, PTEN, Notch-1, CDK2, p53) involved in cell survival and apoptosis, by Real-Time PCR and Western Blotting. We observed a pro-apoptotic, anti-proliferative effect of these compounds in both primary lymphoblasts obtained from patients with T-ALL and in Jurkat cell line. Our results show that both CB2 stimulation and TRPV1 activation, can increase the apoptosis in vitro, interfere with cell cycle progression and reduce cell proliferation, indicating that a new therapeutic approach to T-cell ALL might be possible by modulating CB2 and TRPV1 receptors.

Simple Summary Around 80% of children treated for childhood cancer become long-term survivors. Although chemotherapy and radiotherapy improve survival of these patients, they cause a low-grade chronic inflammation (inflamm-aging) which induces premature aging processes and vital organ failure, a condition known as frailty. Understanding frailty’s biological and molecular mechanisms and identifying inflamm-aging key biomarkers in childhood cancer survivors could be useful to facilitate the screening of comorbidities and to understand whether treatments, used to counteract inflamm-aging, may prevent side effects. Abstract Anti-cancer treatments improve survival in children with cancer. A total of 80% of children treated for childhood cancer achieve 5-year survival, becoming long-term survivors. However, they undergo several chronic late effects related to treatments. In childhood cancer survivors a chronic low-grade inflammation, known as inflamm-aging, is responsible for frailty, a condition characterized by vital organ failure and by premature aging processes. Inflamm-aging is closely related to chemotherapy and radiotherapy, which induce inflammation, accumulation of senescent cells, DNA mutations, and the production of reactive oxygen species. All these conditions are responsible for the onset of secondary diseases, such as osteoporosis, cardiovascular diseases, obesity, and infertility. Considering that the pathobiology of frailty among childhood cancer survivors is still unknown, investigations are needed to better understand frailty’s biological and molecular processes and to identify inflamm-aging key biomarkers in order to facilitate the screening of comorbidities and to clarify whether treatments, normally used to modulate inflamm-aging, may be beneficial. This review offers an overview of the possible biological mechanisms involved in the development of inflamm-aging, focusing our attention on immune system alteration, oxidative stress, cellular senescence, and therapeutic strategies.

Osteosarcoma (OS) is the most severe bone malignant tumor, responsible for altered osteoid deposition and with a high rate of metastasis. It is characterized by heterogeneity, chemoresistance and its interaction with bone microenvironment. The 5-year survival rate is about 67% for patients with localized OS, while it remains at 20% in case of metastases. The standard therapy for OS patients is represented by neoadjuvant chemotherapy, surgical resection, and adjuvant chemotherapy. The most used chemotherapy regimen for children is the combination of high-dose methotrexate, doxorubicin, and cisplatin. Considered that the necessary administration of high-dose chemotherapy is responsible for a lot of acute and chronic side effects, the identification of novel therapeutic strategies to ameliorate OS outcome and the patients’ life expectancy is necessary. In this review we provide an overview on new possible innovative therapeutic strategies in OS.

Tumor-associated macrophages and their alternative activation states together with cytokines and growth factors trapped in tumor microenvironment contribute to the progression of OS. In contrast to other tumor types, M2 polarized macrophages, reduce metastasis and improve survival in osteosarcoma patients. Mifamurtide is an immunomodulatory drug given together with standard adjuvant chemotherapy in high-grade osteosarcoma to improve outcome. Macrophages obtained from peripheral blood mononucleated cells of healthy donors and MG63 cells were cultured alone and together, and treated with Mifamurtide. We analyzed the effects of Mifamurtide on macrophage polarization and on MG63 proliferation, migration and differentiation, evaluating the expression of M1/M2 and osteoblast markers and molecules involved in metastasis and proliferation pathways. Our data suggest that Mifamurtide, switching macrophage polarization towards a TAM-like intermediate M1/M2 phenotype, may modulate the delicate balance between pro-inflammatory and immunomodulatory macrophage functions. Moreover, Mifamurtide may inhibit the cellular proliferation and induce the tumor cell differentiation, probably through the down regulation of pSTAT3, pAKT and IL-17R.

The prognosis for children with recurrent or refractory neuroblastoma remains a significant clinical challenge, and currently there are no known curative salvage regimens. In this paper we investigated the effect of imatinib with rapamycin and the chemotherapeutic agents temozolomide and irinotecan. We treated two children with recurrent neuroblastoma with this so called RIST protocol. Both patients, off therapy for 15 and 31 months, respectively are well, and developing normally, without any complications. These findings suggest that a combination regimen of RIST may provide a therapeutic benefit with a favorable toxicity profile to a unfortunate subset of patients with neuroblastoma.

Background Childhood cancer is relatively uncommon and the European age-standardized rate was 164 new case per million per year among children 0 to 14 years of age (95 % CI 158-170). Aims of our study are to evaluate the cases of these malignant diseases observed between 0 and 15 years of age in the Campania region between 1990 and 2014, the ration between observed and expected cases by disease and province of residence. Also we studied the percentage of extra-regional migration over the time by disease and province of residence. Methods In this study we reported the patients with malignant disease observed in 25 years (1990–2014) based on the specialized registry, the Mod. 1.01 of the AIEOP (Association Italian Pediatric Hematology-Oncology). The size of the monitored population also allowed us to systematically examine five time trends: 1990–94: 1995–99; 2000–04; 2005–09; and 2010–14. Results Between 1990 and 2014 a total of 3655 malignant neoplasms were reported: Napoli province (2059 cases), Salerno province (625), Caserta province (589), Avellino province (229), and Benevento province (153). Epidemiological data suggested that about 4100 cases could be expected in Campania region during the same period. The overall ratio between observed (O) and expected (E) numbers of cases in the five periods considered rose gradually from 0.69 in the first period to 0.76, then 0.82, 0.91, and 0.94, in the other periods considered. The extra-regional migration involved 1029 cases (28.1 %), showing a reduction from 33.7 % of the first period to 20.3 % of the last period considered. Considering single province of residence we observed the lowest rate of migration in Napoli and Caserta province, whereas higher levels were observed in the other provinces. For all provinces, except Salerno, the extra-regional migration declined significantly over time. Conclusions The present findings showed an increase over time of O/E ratio, probably due to improvement in the organization of centers and greater trust of families in local centers. It is possible to further improve the efficiency of healthcare system of Campania region and migration can be reduced with a more rational use of hospitals throughout region.

Osteonecrosis is a significant adverse effect of treatment administered to children suffering from acute lymphoblastic leukemia (ALL) that may have a negative effect on the quality of life. The purpose of this study is to evaluate the rate of secondary vascular osteonecrosis (ON) in a population of pediatric patients with ALL treated with corticosteroids and cytostatic agents. A retrospective analysis of prospectively collected data of the medical records of 328 patients with ALL identified 4 cases with ON, corresponding to 1.2% of all cases observed. Of the 4 patients identified in our study 3 were girls and 1 was a boy, aged from 10 to 16 years old (average age at diagnosis, 12 years). Median time between the diagnosis of ALL and ON was 12.5 months (range, 12 to 36 months). Regarding the lesion size of ON, in all cases the femoral head (monolateral in 1 case and bilateral in 3 cases) was involved and was associated with the scapula-humeral joint in one case. ON of the weight-bearing joints has been identified as a severe complication in chilchildren with leukemia that may be associated with the development of articular surface collapse, subsequent debilitating arthritis, sometimes needing arthroplasty. For this reason it is very important to implement prevention strategies, especially in adolescent girls treated with steroids and chemotherapy. An early diagnosis of ON and careful orthopedic follow-up are necessary in order to avoid bone deformations related to the late start or the wrong therapy. Osteonecrosis is a significant adverse effect of treatment administered to children suffering from acute lymphoblastic leukemia (ALL) that may have a negative effect on the quality of life. The purpose of this study is to evaluate the rate of secondary vascular osteonecrosis (ON) in a population of pediatric patients with ALL treated with corticosteroids and cytostatic agents. A retrospective analysis of prospectively collected data of the medical records of 328 patients with ALL identified 4 cases with ON, corresponding to 1.2% of all cases observed. Of the 4 patients identified in our study 3 were girls and 1 was a boy, aged from 10 to 16 years old (average age at diagnosis, 12 years). Median time between the diagnosis of ALL and ON was 12.5 months (range, 12 to 36 months). Regarding the lesion size of ON, in all cases the femoral head (monolateral in 1 case and bilateral in 3 cases) was involved and was associated with the scapula-humeral joint in one case. ON of the weight-bearing joints has been identified as a severe complication in chilchildren with leukemia that may be associated with the development of articular surface collapse, subsequent debilitating arthritis, sometimes needing arthroplasty. For this reason it is very important to implement prevention strategies, especially in adolescent girls treated with steroids and chemotherapy. An early diagnosis of ON and careful orthopedic follow-up are necessary in order to avoid bone deformations related to the late start or the wrong therapy.

High-dose methotrexate (MTX) is a key component of most treatment protocols for childhood and adolescent non-Hodgkin lymphoma (NHL). Recent studies have suggested that the toxicity of antifolate drugs, such as MTX, is affected by inherited single nucleotide polymorphisms (SNPs) in folate metabolizing genes. The aim of our study was to investigate the potential influence of the C677T and A1298C genetic variants of the methylenetetrahydrofolate reductase (MTHFR) gene on the clinical toxicity and efficacy of MTX in pediatric patients with NHL (n = 95) treated with therapeutic protocols Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) LNH-97 and EURO LB-02. We demonstrated that patients with the 677T genotype had an approximately six-fold greater risk of developing hematological toxicity compared with wild-type carriers, especially in the 1 g/m(2) treatment group (p = 0.01). Moreover, we identified a correlation between the risk of relapse and the T genotype: T carriers had reduced disease-free survival compared with wild-type patients (67% vs. 100%). Our data suggest a pharmacogenetic influence on the adverse effects of high-dose MTX in the 1 g/m(2) treatment group.

Because of the rare occurrence of renal cell carcinoma (RCC) among children very little is known about this malignancy in pediatric age. We aimed adding knowledge on the clinical characteristics and outcome of metastatic (m) RCC in children and adolescents.The series included 14 stage 4 RCC patients with a median age at diagnosis of 155.5 months, observed at the Italian Pediatric Hematology and Oncology Association (AIEOP) centers from January 1973 to November 2010. We were able to reevaluate histopatology of 11 out of the 14 patients and perform immunostaining for TFE3 in 9 out of the 11 patients.Of the 14 patients under study, 5 (3 girls) had a translocation morphology TFE+ RCC, 2 were reassigned as papillary type 1 or 2, respectively, 2 tumor specimens with primary clear cell histology had confirmed the initial histologic diagnosis, and 2-whose biopsy specimen was insufficient-had the diagnosis of RCC not further specified with subtyping. In the remaining 3 cases, the initial diagnosis of clear cell carcinoma was left. Overall, 6 patients received chemotherapy, 9 immunotherapy, and 2 adjuvant antiangiogenic therapy. Overall, 11 patients (78.5%) never achieved complete remission and died from progressive disease 1 to 16 months after diagnosis (median overall survival 5.5 mo). Three patients, 2 of whom received adjuvant antiangiogenic therapy, relapsed to lung at 3, 6, and 8 months after diagnosis, and died 18, 32, and 33 months after diagnosis, respectively.Despite their possibly different biology, childhood and adult mRCC seems to be sharing comparable outcomes. Because of the very low incidence of mRCC (about 20%) in children and adolescents, an international pediatric cooperation to address biological studies and assess the novel targeted approaches is needed.

8503 Background: Little is known about the prognostic role of multidrug resistance (MDR) in newly diagnosed childhood with acute lymphoblastic leukemia (ALL). The aim of this retrospective study was to evaluate in 85 children with ALL the impact of P-glycoprotein 170 (p-gp) product of the mdr-1 gene on achievement of complete remission (CR), and clinical outcome. Methods: MDR-1 protein expression was performed by immunocytochemistry (ICC), and flow cytometry (FC). MDR-1 functional activity was performed by rhodamine (Rhd)-123 efflux test with or without verapamil. All patients enrolled in our study were treated with AIEOP 91–95 protocols. Results: Forty patients (47%) expressed MDR1 protein at significant levels, and 45 (53%) were MDR1 negative. Forty-three of the last patients were also negative for MDR1 function, while 34 out of 40 (85%) patients MDR-1 positive preserved the function. Rhd-123 efflux was inhibited by the MDR modulator verapamil in 12 of 40 (30%) patients. After induction treatment, CR wa...

Background Enhancer of Zeste Drosophila Homologue 2 (EZH2) is a key regulator of transcription as a member of polycomb repressive complex 2 (PRC2) which exerts repression of downstream genes and is correlated to invasiveness and progression of different tumours. Therefore, we evaluated the expression of PRC2 proteins in pediatric soft tissue sarcoma (rhabdomyosarcoma, RMS and extraosseous Ewing sarcoma, EES) correlating them to the clinical outcome of the patients. Methods We analyzed PRC2 protein expression by quantitative real time PCR, western blotting and immunohistochemistry in 17 soft tissue sarcomas (11 RMS and 6 EES) enrolled at Paediatric Oncology Units of the Second University of Naples. Expression analysis was performed for EZH2, SUZ12 and EED. Results Enhancer of Zeste Drosophila Homologue 2 was expressed with a different degree in 60 % of samples. Interestingly, the magnitude of EZH2 up regulation was significantly higher in patients presenting lymph node and/or distant metastases at the diagnosis. Moreover, patients overexpressing EZH2 had a lower probability of survival compared to patients negative or with low EZH2 expression. Conclusions Our study suggests that high EZH2 expression is associated to increased aggressiveness of the disease. Therefore, drugs that control its activity could be potentially used in the epigenetic target treatment of tumors with these alterations.

Studies on activated cell-signaling pathways responsible for neoplastic transformation are numerous in solid tumors and in adult leukemias. Despite of positive results in the evolution of pediatric hematopoietic neoplasias, there are some high-risk subtypes at worse prognosis. The aim of this study was to asses the expression and activation status of crucial proteins involved in cell-signaling pathways in order to identify molecular alterations responsible for the proliferation and/or escape from apoptosis of leukemic blasts. The quantitative and qualitative expression and activation of Erk-1, c-Jun, Caspase8, and Gadd45a was analyzed, by immunocytochemical (ICC) and western blotting methods, in bone marrow blasts of 72 patients affected by acute myeloid leukemia (AML), T-cell acute lymphoblastic leukemia (ALL) and stage IV non-Hodgkin Lymphoma (NHL). We found an upregulation of Erk-1, Caspase8, c-Jun, and Gadd45a proteins with a constitutive activation in 95.8%, 91.7%, 86.2%, 83.4% of analyzed specimens, respectively. It is worth noting that all AML patients showed an upregulation of all proteins studied and the high expression of GADD45a was associated to the lowest DFS median (p = 0.04). On univariate analysis, only Erk-1 phosphorylation status was found to be correlated with a significantly shorter 5-years DFS in all disease subgroups (p = 0.033) and the lowest DFS median in ALL/NHL subgroup (p = 0.04). Moreover, the simultaneous activation of multiple kinases, as we found for c-Jun and Erk-1 (r = 0.26; p = 0.025), might synergistically enhance survival and proliferation potential of leukemic cells. These results demonstrate an involvement of these proteins in survival of blast cells and, consequently, on relapse percentages of the different subgroups of patients. © 2009 D'Angelo et al; licensee BioMed Central Ltd.