Gil Gilad

Invasive fungal infections in pediatric oncology

Data on the epidemiology and outcome of invasive fungal infections in children with cancer are limited. The aim of the study was to delineate the epidemiologic, clinical features, risk factors, and outcome of invasive fungal infections in this population.

Congenital amegakaryocytic thrombocytopenia-3 novel c-MPL mutations and their phenotypic correlations.

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare bone marrow failure syndrome associated with thrombocytopenia and a tendency to progress to aplastic anemia. Mutations in the c-MPL gene encoding for thrombopoietin receptor have been identified in the majority of the patients. Previous studies suggest a genotype-phenotype correlation wherein the severity of the disease depends on the type of mutation present and residual thrombopoietin receptor activity. The present study describes the clinical and genetic findings on a series of 7 patients with CAMT, 3 of them siblings. The patients were homozygous for 5 mutations in the c-MPL gene, including 3 unique ones: c.212+5G>A, C76T, and G1162C. The clinical picture was variable; 1 patient who was homozygous for a nonsense mutation in exon 1 (C76T) developed infantile acute lymphoblastic leukemia, whereas patients who were homozygous for a splice-site mutation (c.212+5G>A) expressing both normal and mutated transcripts had a milder clinical course. As previously suggested, c-MPL mutation analysis in CAMT patients helps to predict the clinical course and to provide optimal therapy.

miR expression profiling at diagnosis predicts relapse in pediatric precursor B-cell acute lymphoblastic leukemia.

Our aim was to identify miRNAs that can predict risk of relapse in pediatric patients with acute lymphoblastic leukemia (ALL). Following high‐throughput miRNA expression analysis (48 samples), five miRs were selected for further confirmation performed by real time quantitative PCR on a cohort of precursor B‐cell ALL patients (n = 138). The results were correlated with clinical parameters and outcome. Low expression of miR‐151‐5p, and miR‐451, and high expression of miR‐1290 or a combination of all three predicted inferior relapse free survival (P = 0.007, 0.042, 0.025, and <0.0001, respectively). Cox regression analysis identified aberrant expression of the three miRs as an independent prognostic marker with a 10.5‐fold increased risk of relapse (P = 0.041) in PCR‐MRD non‐high risk patients. Furthermore, following exclusion of patients harboring IKZF1 deletion, the aberrant expression of all three miRs could identify patients with a 24.5‐fold increased risk to relapse (P < 0.0001). The prognostic relevance of the three miRNAs was evaluated in a non‐BFM treated precursor B‐cell ALL cohort (n = 33). A significant correlation between an aberrant expression of at least one of the three miRs and poor outcome was maintained (P < 0.0001). Our results identify an expression profile of miR‐151‐5p, miR‐451, and miR‐1290 as a novel biomarker for outcome in pediatric precursor B‐cell ALL patients, regardless of treatment protocol. The use of these markers may lead to improved risk stratification at diagnosis and allow early therapeutic interventions in an attempt to improve survival of high risk patients.

Growth and pubertal patterns in young survivors of childhood acute lymphoblastic leukemia.

Abstract Background: Survivors of acute lymphoblastic leukemia (ALL) may experience endocrine dysfunction. This study evaluated growth and pubertal patterns in survivors of childhood ALL. Methods: Longitudinal assessment of anthropometric measurements and pubertal status was performed in a retrospective cohort of survivors (n=183). Median age at last endocrine visit was 16.1 years (range 8.2–27.6); median follow-up time was 8.7 years (range 3–21.4). Results: Treatment with chemotherapy+prophylactic cranial radiation (pCRT, n=29) was associated with lower mean height standard deviation score (SDS) than chemotherapy alone (n=154) (p=0.001) and higher prevalence of adult short stature (13% vs. 2.2%). Mean age at pubertal onset was normal (girls: 10.3±1.3 years; boys: 12.0±1.3 years). Precocious puberty, diagnosed in 8.7% of patients, was more prevalent in pCRT-treated girls. Rates of overweight and obesity were 22.9% and 9.3%, respectively. Predictors of endocrine disorders were pCRT (p=0.031) and female gender (p=0.041); of obesity, higher body mass index (BMI)-SDS at diagnosis (p=0.001); and of short stature, lower height-SDS at diagnosis (p=0.038). Conclusions: Most childhood ALL survivors given chemotherapy alone attain normal adult height and puberty. Childhood ALL survivors are at increased risk of overweight, especially those with increased BMI at diagnosis. Clinicians should screen for overweight early in survivorship and introduce early interventions.

Abstract B34: Increased risk of relapse in non-high-risk children with pediatric B-lineage acute lymphoblastic leukemia can be predicted at diagnosis by microRNA expression

Aim: microRNAs (miRNAs) have been implicated in many malignancies. Our aim was to identify specific miRNAs that can predict risk of relapse in pediatric acute lymphoblastic leukemia (ALL) patients treated on BFM protocols, better than the current risk group stratification. Currently, the main method for risk group stratification is based on the amount of minimal residual disease (MRD) assessed at specific time points by real time quantitative PCR (RQ-PCR). Material and methods: Following microRNA expression analysis, we decided to focus on miR-151-5p and miR-451 that significantly correlated with known prognostic factors in ALL. Validation was performed by measuring the expression levels of miR-151-5p and miR-451 by RQ- PCR on a cohort of B-lineage ALL patients treated by a Berlin-Frankfurt-Munster (BFM) protocol following exclusion of Philadelphia positive patients (n=123). Results: Low expression of miR-151-5p, miR-451 or of both together resulted in significantly worse relapse free survival (RFS) (61%, 64% and 43%, respectively) compared to RFS rates when either or both miRNAs were highly expressed (83%, 82% and 82%, respectively) (p=0.023, 0.03 and 0.0001, respectively). Multivariate Cox regression analysis identified low expression of both miRNAs as an independent prognostic marker. Patients expressing low expression levels of both miRs had a 8.8-fold increased risk for relapse (p=0.003). Deletion of IKZF1 gene is a known adverse prognostic marker in B-lineage ALL. In 88 patients, IKZF1 status was analyzed and 9 patients were found to harbor the deletion. The expression of both miRs could still identify an adverse group of patients with only 50% RFS within the group with no deletion (p Even in a non-BFM treated B-lineage ALL cohort from The Netherlands, the expression levels of both miRs significantly correlated with outcome (p=0.003). Conclusion: Our results identify miR-151-5p and miR-451 as novel biomarkers for outcome in pediatric B-lineage ALL patients, regardless of treatment protocol. This may lead to improved risk group stratification and better RFS. Citation Format: Smadar Avigad, Iedan RN Verly, Gertjan JL Kaspers, Jacqueline Cloos, Anat Ohali, Michal Hameiri-Grossman, Keren Shichrur, Eva Fronkova, Jan Trka, Drorit Luria, Yona Kodman, Hadar Mirsky, Dafna Gaash, Marta Jeison, Galia Avrahami, Sarah Elitzur, Gil Gilad, Batia Stark, Isaac Yaniv. Increased risk of relapse in non-high-risk children with pediatric B-lineage acute lymphoblastic leukemia can be predicted at diagnosis by microRNA expression. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr B34.