18 F-FDG-PET/CT imaging in diagnostic workup of pediatric precursor B-cell lymphoblastic lymphoma.

18 F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) imaging is currently not used in standard diagnostics for B-cell precursor lymphoblastic lymphoma (BCP-LBL), and it is unknown whether PET/CT imaging would lead to agreement between detection of lesions with the gold standard imaging methods. Therefore, we performed a retrospective cohort study in which we included 32 pediatric BCP-LBL patients and determined localizations by reviewing local imaging reports. There was a disagreement between protocol-based imaging and PET/CT in 59% of the patients, and the discrepancies mostly comprise of additional lesions detected with PET/CT, typically in lymph node and bone or the absence of bone marrow involvement with PET/CT. If PET/CT was leading in determining definite stage of disease, this would lead to a different stage and therapy branch in 31% and 28% of the patients, respectively.

Liver involvement in pediatric Hodgkin lymphoma: A systematic review by an international collaboration on Staging Evaluation and Response Criteria Harmonization (SEARCH) for Children, Adolescent, and Young Adult Hodgkin Lymphoma (CAYAHL).

Hepatic involvement in Hodgkin lymphoma (HL) is uncommon (∼5% of patients) but always implies stage IV disease. Accurate staging is mandatory for making the appropriate risk assignment and treatment decisions. The Staging Evaluation and Response Criteria Harmonization for Childhood, Adolescent and Young Adult Hodgkin Lymphoma (SEARCH for CAYAHL) international working group conducted a systematic literature review of liver involvement in HL patients with the aim to propose a universally acceptable definition for liver involvement in pediatric HL. Thirty-three articles describing 6985 pediatric and adult HL patients were reviewed, of which 539 (7.7%) mentioned liver involvement. The literature did not provide a uniform definition of hepatic involvement and we propose consensus criteria derived from the EuroNet and Children's Oncology Group protocols, where liver involvement is defined as any hepatic lesion on computed tomography scan that correlates with 18 F-FDG uptake greater than background liver. A clear definition of liver lesions is necessary to consistently identify liver involvement and compare its impact on outcomes among protocols worldwide.

Dosage of 6-Mercaptopurine in Relation to Genetic TPMT and ITPA Variants: Toward Individualized Pediatric Acute Lymphoblastic Leukemia Maintenance Treatment.

6-mercaptopurine (6-MP) is the mainstay in pediatric acute lymphoblastic leukemia (ALL) maintenance treatment. Variants in genes coding for thiopurine S-methyl transferase (TPMT) and inosine triphosphate pyrophosphatase (ITPA) are known to influence 6-MP metabolism. We determined TPMT and ITPA genotype and enzyme activity and the mean 6-MP doses during maintenance treatment in 40 children treated for ALL according to the Dutch Childhood Oncology Group (DCOG)-ALL11 protocol in the Radboudumc Amalia Children's Hospital, Nijmegen, The Netherlands. Patients with genetic variants in TPMT (N=3) had significantly lower TPMT enzyme activity (mean 0.46 vs. 0.72 µmol/mmol hemoglobin/h, P=0.005). Although the difference was not statistically significant, they were treated with lower mean 6-MP doses (28.1 mg/m [SD 25.5 mg/m] vs. 41.3 mg/m [SD 17.2 mg/m], P=0.375). In patients with genetic ITPA variants (N=21), ITPA enzyme activity was significantly lowered (mean 3.67 vs. 6.84 mmol/mmol hemoglobin/h, P<0.0005). The mean 6-MP doses did not differ between patients with and without variants in ITPA (40.0 mg/m [SD 20.3 mg/m] vs. 40.6 mg/m [SD 14.9 mg/m], P=0.663). The TPMT genotype, but not the ITPA genotype, should be considered as part of standard evaluation before starting ALL maintenance treatment.

Pancytopenia and Hypothyroidism in a Patient With Leukemic Infiltration of the Thyroid as the First Presentation of Acute Lymphoblastic Leukemia.

We report the case of a 16-year-old female patient with hypothyroidism, goiter, and pancytopenia. Biopsy of the thyroid showed leukemic infiltration. After confirmation of the diagnosis of B-lymphoblastic leukemia, treatment was started. Histologic follow-up at day 33 and 79 showed no residual signs of leukemic infiltration. Hypothyroidism persisted despite successful antileukemic treatment. Leukemic infiltration of the thyroid should be considered as a differential diagnosis in patients with hypothyroidism, goiter, and pancytopenia. We suggest that follow-up of thyroid function and histology should be incorporated in the follow-up of rare patients with acute lymphoblastic leukemia with thyroid infiltration.

NOTCH1 fusions in pediatric T-cell lymphoblastic lymphoma: A high-risk subgroup with CCL17 (TARC) levels as diagnostic biomarker.

Twenty percent of children with T-cell lymphoblastic lymphoma (T-LBL) will relapse and have an extremely poor outcome. Currently, we can identify a genetically low-risk subgroup in pediatric T-LBL, yet these high-risk patients who need intensified or alternative treatment options remain undetected. Therefore, there is an urgent need to recognize these high-risk T-LBL patients through identification of molecular characteristics and biomarkers. By using RNA sequencing which was performed in 29/49 T-LBL patients who were diagnosed in the Princess Maxima Center for Pediatric Oncology between 2018 and 2023, we discovered a previously unknown high-risk biological subgroup of children with T-LBL. This subgroup is characterized by NOTCH1 gene fusions, found in 21% of our T-LBL cohort (6/29). All patients presented with a large mediastinal mass, pleural/pericardial effusions, and absence of blasts in the bone marrow, blood, and central nervous system. Blood CCL17 (C-C Motif Chemokine Ligand 17, TARC) levels were measured at diagnosis in 26/29 patients, and all six patients with NOTCH1 gene fusions patients exclusively expressed highly elevated blood CCL17 levels, defining a novel and previously not known clinically relevant biomarker for T-cell lymphoblastic lymphoma. Four out of these six patients relapsed during therapy, a fifth developed a therapy-related acute myeloid leukemia during maintenance therapy. These data indicate that T-LBL patients with a NOTCH1 fusion have a high risk of relapse which can be easily identified using a blood CCL17 screening at diagnosis. Further molecular characterization through NOTCH1 gene fusion analysis offers these patients the opportunity for treatment intensification or new treatment strategies.

Survival trends and long-term toxicity in pediatric patients with osteosarcoma.

Background. This study was conducted to investigate the clinical characteristics and treatment results of osteosarcoma in pediatric patients during the past 30 years. Trends in survival rates and long-term toxicity were analyzed. Procedure. 130 pediatric patients under the age of 20 years with primary localized or metastatic high-grade osteosarcoma were analyzed regarding demographic, treatment-related variables, long-term toxicity, and survival data. Results. Comparison of the different time periods of treatment showed that the 5-year OS improved from 58.6% for children diagnosed during 1979-1983 to 78.6% for those diagnosed during 2003-2008 (P = 0.13). Interestingly, the basic treatment agents including cisplatin, doxorubicin, and methotrexate remained the same. Treatment reduction due to acute toxicity was less frequent in patients treated in the last era (7.1% versus 24.1% in patients treated in 1979-1983; P = 0.04). Furthermore, late cardiac effects and secondary malignancies can become evident many years after treatment. Conclusion. We elucidate the prevalence of toxicity to therapy of patients with osteosarcoma over the past 30 years. The overall improvement in survival may in part be attributed to improved supportive care allowing regimens to be administered to best advantage with higher tolerance of chemotherapy and therefore less chemotherapy-related toxicity.

High Prevalence of Constitutional Mismatch Repair Deficiency in a Pediatric T-cell Lymphoblastic Lymphoma Cohort.

This study describes the clinical characteristics of a complete Dutch T-cell lymphoblastic lymphoma (T-LBL) cohort, including second primary malignancies and comorbidities. We show that over 10% of patients in this complete T-LBL cohort have been diagnosed with a cancer predisposition syndrome (CPS), consisting almost exclusively of constitutional mismatch repair deficiency (CMMRD). The clinical characteristics of sporadic T-LBL patients were compared with T-LBL patients that have been diagnosed with CMMRD. This shows that disease presentation is comparable but that disease localization in CMMRD patients might be more localized. The percentage of CPS seems reliable considering the completeness of the cohort of Dutch T-LBL patients and might even be an underestimation (possibility of undiagnosed CPS patients in cohort). As the frequency of an underlying predisposition syndrome among T-LBL patients may be underestimated at present, we advocate for screening all pediatric T-LBL patients for the presence of germline mutations in mismatch repair genes.

Pediatric Precursor B-Cell Lymphoblastic Malignancies: From Extramedullary to Medullary Involvement.

B-cell lymphoblastic lymphoma (BCP-LBL) and B-cell acute lymphoblastic leukemia (BCP-ALL) are the malignant counterparts of immature B-cells. BCP-ALL is the most common hematological malignancy in childhood, while BCP-LBL accounts for only 1% of all hematological malignancies in children. Therefore, BCP-ALL has been well studied and treatment protocols have changed over the last decades, whereas treatment for BCP-LBL has stayed roughly the same. Clinical characteristics of 364 pediatric patients with precursor B-cell malignancies were studied, consisting of BCP-LBL (n = 210) and BCP-ALL (n = 154) patients. Our results indicate that based on the clinical presentation of disease, B-cell malignancies probably represent a spectrum ranging from complete isolated medullary disease to apparent complete extramedullary disease. Hepatosplenomegaly and peripheral blood involvement are the most important discriminators, as both seen in 80% and 95% of the BCP-ALL patients and in 2% of the BCP-LBL patients, respectively. In addition, we show that the overall survival rates in this cohort differ significantly between BCP-LBL and BCP-ALL patients aged 1−18 years (p = 0.0080), and that the outcome for infants (0−1 years) with BCP-LBL is significantly decreased compared to BCP-LBL patients of all other pediatric ages (p < 0.0001).

SLC7A8 coding for LAT2 is associated with early disease progression in osteosarcoma and transports doxorubicin.

Background: Despite (neo) adjuvant chemotherapy with cisplatin, doxorubicin and methotrexate, some patients with primary osteosarcoma progress during first-line systemic treatment and have a poor prognosis. In this study, we investigated whether patients with early disease progression (EDP), are characterized by a distinctive pharmacogenetic profile. Methods and Findings: Germline DNA from 287 Dutch high-grade osteosarcoma patients was genotyped using the DMET Plus array (containing 1,936 genetic markers in 231 drug metabolism and transporter genes). Associations between genetic variants and EDP were assessed using logistic regression models and associated variants (p <0.05) were validated in independent cohorts of 146 (Spain and United Kingdom) and 28 patients (Australia). In the association analyses, EDP was significantly associated with an SLC7A8 locus and was independently validated (meta-analysis validation cohorts: OR 0.19 [0.06-0.55], p = 0.002). The functional relevance of the top hits was explored by immunohistochemistry staining and an in vitro transport models. SLC7A8 encodes for the L-type amino acid transporter 2 (LAT2). Transport assays in HEK293 cells overexpressing LAT2 showed that doxorubicin, but not cisplatin and methotrexate, is a substrate for LAT2 (p < 0.0001). Finally, SLC7A8 mRNA expression analysis and LAT2 immunohistochemistry of osteosarcoma tissue showed that the lack of LAT2 expression is a prognostic factor of poor prognosis and reduced overall survival in patients without metastases (p = 0.0099 and p = 0.14, resp.). Conclusion: This study identified a novel locus in SLC7A8 to be associated with EDP in osteosarcoma. Functional studies indicate LAT2-mediates uptake of doxorubicin, which could give new opportunities to personalize treatment of osteosarcoma patients.

Taqman genotyping assays can be used on decalcified and paraffin-embedded tissue from patients with osteosarcoma.

BACKGROUND: In cancers like osteosarcoma with a 5-year overall survival of 50-60%, archived histological specimens can be a useful source of biological material. However, this material generally has been decalcified and formalin-fixed for many years. In our study, we investigated whether DNA obtained from these tissues can be used for reliable single nucleotide polymorphism (SNP) genotyping. PROCEDURE: We studied two SNPs in the drug transporter MDR1 using Taqman® SNP genotyping assays. Genotypes of the germ line DNA derived from freshly isolated DNA of 20 surviving patients with osteosarcoma were compared with genotypes obtained from archived material from decalcified formalin-fixed, paraffin-embedded (FFPE) blocks of the same patients. RESULTS: Decalcified FFPE-derived DNA yielded smaller PCR fragments compared to DNA extracted from peripheral blood cells, with a reliable size of ∼200 bp. However, we were able to evaluate each SNP in 19 of 20 cases included in this study. All successfully genotyped samples showed 100% concordance between genotypes obtained from DNA of FFPE tissue and the genotypes obtained from DNA of blood from the same patients. CONCLUSIONS: In conclusion, we have demonstrated that decalcified FFPE tissue can be used for genetic polymorphism analysis using Taqman® allelic discrimination assays. This forms a unique opportunity to combine new insights in genetic research with historical patient cohorts.

Severe toxicity free survival: physician-derived definitions of unacceptable long-term toxicities following acute lymphocytic leukaemia.

5-year overall survival rates have surpassed 90% for childhood acute lymphocytic leukaemia, but survivors are at risk for permanent health sequelae. Although event-free survival appropriately represents the outcome for cancers with poor overall survival, this metric is inadequate when cure rates are high but challenged by serious, persistent complications. Accordingly, a group of experts in paediatric haematology-oncology, representative of 17 international acute lymphocytic leukaemia study groups, launched an initiative to construct a measure, designated severe toxicity-free survival (STFS), to quantify the occurrence of physician-prioritised toxicities to be integrated with standard cancer outcome reporting. Five generic inclusion criteria (not present before cancer diagnosis, symptomatic, objectifiable, of unacceptable severity, permanent, or requiring unacceptable treatments) were used to assess 855 health conditions, which resulted in inclusion of 21 severe toxicities. Consensus definitions were reached through a modified Delphi process supplemented by two additional plenary meetings. The 21 severe toxicities include severe adverse health conditions that substantially affect activities of daily living and are refractory to therapy (eg, refractory seizures), are without therapeutic options (eg, blindness), or require substantially invasive treatment (eg, cardiac transplantation). Incorporation of STFS assessment into clinical trials has the potential to improve and diversify treatment strategies, focusing not only on traditional outcome events and overall survival but also the frequencies of the most severe toxicities. The two major aims of this Review were to: prioritise and define unacceptable long-term toxicity for patients with childhood acute lymphocytic leukaemia, and define how these toxicities should be combined into a composite quantity to be integrated with other reported outcomes. Although STFS quantifies the clinically unacceptable health tradeoff for cure using childhood acute lymphocytic leukaemia as a model disease, the prioritised severe toxicities are based on generic considerations of relevance to any other cancer diagnosis and age group.

Pharmacogenomics as a Tool to Limit Acute and Long-Term Adverse Effects of Chemotherapeutics: An Update in Pediatric Oncology.

In the past decades, new cancer treatments have been introduced in pediatric oncology leading to improvement in clinical outcomes and survival rates. However, due to inter-individual differences, some children experience severe chemotherapy-induced toxicities or a poor clinical outcome. An explanation for the diversity in response to chemotherapy is genetic variation, leading to differences in expression and activity of metabolizing and transport enzymes as well as drug targets. Pharmacogenetic testing has emerged as a promising tool to predict and limit acute and long-term adverse effects in patients. However, in pediatric oncology, limited number of patients and a considerable diversity in study results complicate the interpretation of test results and its clinical relevance. With this review, we provide an overview of new developments over the past four years regarding relevant polymorphisms related to toxicity in pediatric oncology. The following chemotherapeutics and associated toxicities are discussed: alkylating agents, anthracyclines, asparaginase, methotrexate, platinum compounds, steroids, thiopurines, topoisomerase inhibitors, and vinca alkaloids. Our review identifies several questions regarding the role of genetic variants in chemotherapy-induced toxicities. Ambiguities in the literature stem from small population sizes, differences in (statistical) interpretation and variations in sequencing technologies as well as different clinical outcome definitions. Standardization of clinical outcome data and toxicity definitions within electronic health records combined with the increased availability of genomic sequence techniques in clinical practice will help to validate these models in upcoming years.

Analysis of Drug Metabolizing Gene Panel in Osteosarcoma Patients Identifies Association Between Variants in SULT1E1, CYP2B6 and CYP4F8 and Methotrexate Levels and Toxicities.

High-dose methotrexate is a cornerstone agent in the chemotherapeutic treatment of patients with osteosarcoma. However, patients often develop methotrexate-induced toxicities. We aim to identify determinants of methotrexate-induced toxicities in osteosarcoma patients by investigating the relation between drug plasma levels, methotrexate-induced toxicities, and germline variants in genes related to drug absorption, distribution, metabolism, and elimination. A cohort of 114 osteosarcoma patients was genotyped for 1,931 variants in 231 genes using the Drug Metabolism Enzymes and Transporters Plus array. Methotrexate plasma levels and laboratory measurements during and after high-dose methotrexate treatment concerning renal function, liver damage, and myelopoiesis to reflect toxicity outcomes were obtained. One hundred and thirteen patients and a subset of 545 variants in 176 genes passed quality control checks. Methotrexate plasma levels showed associations with creatinine, alanine aminotransferase, and hemoglobin. Genetic variant rs3736599 in the 5'-untranslated region of SULT1E1 was associated with lower 48 hour methotrexate plasma levels [coef -0.313 (95% CI -0.459 - -0.167); p = 2.60 × 10-5]. Association with methotrexate-induced decreased thrombocyte counts was found for two intronic variants in CYP2B6 {rs4803418 [coef -0.187 (95% CI -0.275 - -0.099); p = 3.04 × 10-5] and rs4803419 [coef -0.186 (95% CI -0.278 - -0.093); p = 8.80 × 10-5]}. An association with increased thrombocyte counts was identified for the intronic variant rs4808326 in CYP4F8 [coef 0.193 (95% CI 0.099 - 0.287); p = 6.02 × 10-5]. Moreover, a secondary analysis with a binary approach using CTCAE toxicity criteria resulted in a nominal significant associations (p < 0.05) for two out of three variants (rs4803418 and rs4808326). This is the first study to identify genetic variants in SULT1E1, CYP2B6, and CYP4F8 to be associated with methotrexate pharmacokinetics and toxicities. Validation of these variants in an independent cohort and further functional investigation of variants in the identified genes is needed to determine if and how they affect methotrexate plasma levels and the development of methotrexate-induced toxicities.

A First Step toward Personalized Medicine in Osteosarcoma: Pharmacogenetics as Predictive Marker of Outcome after Chemotherapy-Based Treatment.

PURPOSE: Overall survival in patients with osteosarcoma is only 60%. Poor response to chemotherapy is the dominant risk factor for poor survival. Pharmacogenetic research can offer possibilities to optimize treatment and improve outcome. We applied a pathway-based approach to evaluate the cumulative effect of genes involved in the metabolism of cisplatin and doxorubicin in relationship to clinical outcome. EXPERIMENTAL DESIGN: We included 126 patients with osteosarcoma. To comprehensively assess common genetic variation in the 54 genes selected, linkage disequilibrium (LD; r(2) = 0.8)-based tag-single nucleotide polymorphisms (SNP) strategy was used. A final set of 384 SNPs was typed using Illumina Beadarray platform. SNPs significantly associated with 5-year progression-free survival (PFS) were replicated in another 64 patients with osteosarcoma. RESULTS: We identified five variants in FasL, MSH2, ABCC5, CASP3, and CYP3A4 that were associated with 5-year PFS. Risk stratification based on the combined effects of the risk alleles showed a significant improvement of 5-year PFS. Patients that carried no or only one risk allele had a 5-year PFS of 100% compared with a 5-year PFS of 84.4% for carriers of two or three risk alleles, 66.7% PFS if a patient carried four to five alleles, and a 5-year PFS of 41.8% for patients with >5 risk alleles (P < 0.001). CONCLUSIONS: We identified several genes that showed association with PFS in patients with osteosarcoma. These pharmacogenetic risk factors might be useful to predict treatment outcome and to stratify patients immediately after diagnosis and offer the possibility to improve treatment and outcome.

Influence of genetic variants in TPMT and COMT associated with cisplatin induced hearing loss in patients with cancer: two new cohorts and a meta-analysis reveal significant heterogeneity between cohorts.

Treatment with cisplatin-containing chemotherapy regimens causes hearing loss in 40-60% of cancer patients. It has been suggested that genetic variants in the genes encoding thiopurine S-methyltransferase (TPMT) and catechol O-methyltransferase (COMT) can predict the development of cisplatin-induced ototoxicity and may explain interindividual variability in sensitivity to cisplatin-induced hearing loss. Two recently published studies however, sought to validate these findings and showed inconsistent results. The aim of this study was to evaluate the role of polymorphisms in the TPMT and COMT genes in cisplatin-induced ototoxicity. Therefore we investigated two independent cohorts of 110 Dutch and 38 Spanish patients with osteosarcoma and performed a meta-analysis including all previously published studies resulting in a total population of 664 patients with cancer. With this largest meta-analysis performed to date, we show that the influence of TPMT and COMT on the development of cisplatin-induced hearing loss may be less important than previously suggested.

Foreign adopted children are a source of methicillin-resistant Staphylococcus aureus transmission to countries with low prevalence.

We report a 13.0% prevalence rate of methicillin-resistant Staphylococcus aureus (MRSA) carriers in foreign adopted children, who are frequently hospitalized within the first year after arrival. Hospitalization in the country of origin and special need status are no significant risk factors for MRSA colonization. Healthcare workers are overrepresented among their adoptive parents. These children represent a potential source of MRSA transmission into the healthcare system.

Age as prognostic factor in patients with osteosarcoma.

Age at diagnosis is a well known prognostic factor in many different malignancies; its significance for patients with osteosarcoma is however controversial. To gain more insight in the prognostic role of age, we performed a retrospective study at our institute. We included 102 patients with de-novo osteosarcoma and formed three age groups to evaluate age specific survival rates: ≤ 14 years, 15-19 years and 20-40 years. Differences in outcome between patients aged 15-19 years treated at either the pediatric department or the adult department of oncology were evaluated. The 5-year overall survival rate (OSR) of the whole population was 53.5%±1.5%. OSR of 70.6%±0.8% was seen in patients ≤ 14 years old, 52.5%±1.1% in patients 15-19 years old and 33.3%±0.9% in the patients aged 20-40 years (p=0.01). Significant differences were observed with regard to stage at presentation (higher in older age groups), size of the tumor (larger in younger age groups) and histological response (more good responders in younger age groups). No significant difference was seen between outcomes of patients aged 15-19 years treated at the pediatric or adult oncology department. In conclusion, younger patients have a significantly better outcome than older patients.

Hematopoietic stem cell transplantation corrects the immunologic abnormalities associated with immunodeficiency-centromeric instability-facial dysmorphism syndrome.

Immunodeficiency-centromeric instability-facial dysmorphism syndrome, characterized by variable immunodeficiency, centromeric instability, and facial anomalies caused by epigenetic dysregulation resulting in hypomethylation, is caused in many patients by mutations in DNMT3B, a DNA methyltransferase gene; associated infections are a major cause of serious sequelae and death. Hematopoietic stem cell transplantation may improve the clinical course in immunodeficiency-centromeric instability-facial dysmorphism syndrome. We report 3 unrelated patients with persistent infections and intestinal complications who successfully underwent hematopoietic stem cell transplantation after nonmyeloablative or myeloablative conditioning regimens using HLA-matched donors. In all cases, donor chimerism led to resolution of intestinal complications and infections, growth improvement, and correction of the immunodeficiency.