Riitta Niinimäki

High Body Mass Index Increases the Risk for Osteonecrosis in Children With Acute Lymphoblastic Leukemia

PURPOSE The aim of the study was to determine the incidence of and clinical risk factors for radiographic osteonecrosis (ON) in children treated for acute lymphoblastic leukemia (ALL) using the Nordic ALL protocols. PATIENTS AND METHODS Ninety-seven consecutive patients with childhood ALL were studied prospectively by magnetic resonance imaging (MRI) of the lower extremities at the end of the treatment. RESULTS Twenty-three (24%) of the 97 patients had ON. Seven of the patients (30%) were symptomatic, and three patients (13%) required surgical interventions. Multiple logistic regression analysis showed that high body mass index (BMI; P = .04), female sex (P = .01), older age at diagnosis (P < .001), and higher cumulative dexamethasone dose (P = .03) were independent risk factors for radiographic ON. The cumulative prednisone dose did not differ significantly between the patients with and without ON. The incidence of radiographic ON decreased significantly, from 36% to 7%, when the duration of dexamethasone exposure during the delayed-intensification phase was shortened from 3 to 4 weeks to 2 weeks with a taper (P = .001). CONCLUSION ON as determined by MRI was found to be a common complication in children and adolescents after treatment with the Nordic ALL protocols. Revision of the ALL protocols by shortening the single exposure to dexamethasone has diminished the risk for ON remarkably. High BMI was identified as a new significant risk factor for ON.

Consensus definitions of 14 severe acute toxic effects for childhood lymphoblastic leukaemia treatment: a Delphi consensus

Although there are high survival rates for children with acute lymphoblastic leukaemia, their outcome is often counterbalanced by the burden of toxic effects. This is because reported frequencies vary widely across studies, partly because of diverse definitions of toxic effects. Using the Delphi method, 15 international childhood acute lymphoblastic leukaemia study groups assessed acute lymphoblastic leukaemia protocols to address toxic effects that were to be considered by the Ponte di Legno working group. 14 acute toxic effects (hypersensitivity to asparaginase, hyperlipidaemia, osteonecrosis, asparaginase-associated pancreatitis, arterial hypertension, posterior reversible encephalopathy syndrome, seizures, depressed level of consciousness, methotrexate-related stroke-like syndrome, peripheral neuropathy, high-dose methotrexate-related nephrotoxicity, sinusoidal obstructive syndrome, thromboembolism, and Pneumocystis jirovecii pneumonia) that are serious but too rare to be addressed comprehensively within any single group, or are deemed to need consensus definitions for reliable incidence comparisons, were selected for assessment. Our results showed that none of the protocols addressed all 14 toxic effects, that no two protocols shared identical definitions of all toxic effects, and that no toxic effect definition was shared by all protocols. Using the Delphi method over three face-to-face plenary meetings, consensus definitions were obtained for all 14 toxic effects. In the overall assessment of outcome of acute lymphoblastic leukaemia treatment, these expert opinion-based definitions will allow reliable comparisons of frequencies and severities of acute toxic effects across treatment protocols, and facilitate international research on cause, guidelines for treatment adaptation, preventive strategies, and development of consensus algorithms for reporting on acute lymphoblastic leukaemia treatment.

Gain-of-function SAMD9L mutations cause a syndrome of cytopenia, immunodeficiency, MDS and neurological symptoms

Several monogenic causes of familial myelodysplastic syndrome (MDS) have recently been identified. We studied 2 families with cytopenia, predisposition to MDS with chromosome 7 aberrations, immunodeficiency, and progressive cerebellar dysfunction. Genetic studies uncovered heterozygous missense mutations in SAMD9L, a tumor suppressor gene located on chromosome arm 7q. Consistent with a gain-of-function effect, ectopic expression of the 2 identified SAMD9L mutants decreased cell proliferation relative to wild-type protein. Of the 10 individuals identified who were heterozygous for either SAMD9L mutation, 3 developed MDS upon loss of the mutated SAMD9L allele following intracellular infections associated with myeloid, B-, and natural killer (NK)-cell deficiency. Five other individuals, 3 with spontaneously resolved cytopenic episodes in infancy, harbored hematopoietic revertant mosaicism by uniparental disomy of 7q, with loss of the mutated allele or additional in cisSAMD9L truncating mutations. Examination of 1 individual indicated that somatic reversions were postnatally selected. Somatic mutations were tracked to CD34+ hematopoietic progenitor cell populations, being further enriched in B and NK cells. Stimulation of these cell types with interferon (IFN)-α or IFN-γ induced SAMD9L expression. Clinically, revertant mosaicism was associated with milder disease, yet neurological manifestations persisted in 3 individuals. Two carriers also harbored a rare, in trans germ line SAMD9L missense loss-of-function variant, potentially counteracting the SAMD9L mutation. Our results demonstrate that gain-of-function mutations in the tumor suppressor SAMD9L cause cytopenia, immunodeficiency, variable neurological presentation, and predisposition to MDS with -7/del(7q), whereas hematopoietic revertant mosaicism commonly ameliorated clinical manifestations. The findings suggest a role for SAMD9L in regulating IFN-driven, demand-adapted hematopoiesis.

Osteonecrosis in children treated for lymphoma or solid tumors.

Purpose The purpose of this study was to find out the incidence of and clinical risk factors for magnetic resonance imaging (MRI)-detected osteonecrosis (ON) in children treated for lymphoma or solid tumors. Patients and Methods The development of ON was studied in 32 childhood cancer patients who underwent MRI scanning of the lower extremities at the end of their treatment. The underlying malignancy was Wilms tumor in 8 patients, non-Hodgkin lymphoma (NHL) in 8, Hodgkin disease (HD) in 7, rhabdomyosarcoma in 6, and other occasional solid tumors in 3 patients. Results Six of the 32 patients (19%) had ON. The mean age of the patients with ON at diagnosis was 12.7 years compared with 5.8 years for the patients without ON (P<0.001). All the patients with ON had either HD (4 patients) or NHL (2 patients). Two (33%) of the patients with ON were symptomatic. Conclusions ON in MRI was found to be a common complication in children after treatment for HD or NHL. The risk for ON seems to be very low in patients with other solid tumors even when they receive high cumulative doses of dexamethasone.

Leukemic blasts are present at low levels in spinal fluid in one-third of childhood acute lymphoblastic leukemia cases.

Central nervous system (CNS) involvement is associated with relapse in childhood acute lymphoblastic leukemia (ALL) and is a diagnostic challenge.

The diagnosis and classification of osteonecrosis in patients with childhood leukemia

Osteonecrosis is a well‐recognized complication in patients with childhood leukemia. Its clinical relevance is highly dependent on the size and location of the lesion. Therefore, the diagnosis, description of the affected site and the classification of the disease, must be precise. We conducted an extensive literature review to assess the quality of studies reporting the incidence of osteonecrosis in patients with childhood leukemia. Of the 31 included studies, one‐third (32% [n = 10]) did not describe the diagnostic method that was used to assess osteonecrosis. In almost two‐third (61% [n = 19]) of the studies, the osteonecrosis classification system was not used. We conclude that the quality of most published studies on the incidence of osteonecrosis in patients with childhood leukemia is relatively poor because many studies did not describe the radiological method used to diagnose osteonecrosis and/or did not use a validated osteonecrosis classification system. To compare the incidence of osteonecrosis, and to assess the severity and clinical consequences of osteonecrosis in patients with childhood leukemia, there is a need for a robust and widely recognized classification system to grade all cases of osteonecrosis despite the site of lesion. Pediatr Blood Cancer 2015;62:198–203.

Bone marrow failure syndrome caused by homozygous frameshift mutation in the ERCC6L2 gene

Inherited bone marrow failure syndromes (IBMFS) are group of disorders that lead to inadequate production of blood cells. Mutations in genes involved in telomere maintenance, DNA repair, and the cell cycle cause IBMFS. ERCC6L2 gene mutations have been associated with bone marrow failure that includes developmental delay and microcephaly. We report 2 cases of bone marrow failure with no extra‐hematopoietic manifestations in patients from unrelated families with a homozygous truncating mutation in ERCC6L2. Bone marrow failure without developmental delay or microcephaly with ERCC6L2 mutation has not been previously described.

Role of neuroimaging in children with acute lymphoblastic leukemia and central nervous system involvement at diagnosis.

Each year approximately 200 children and adolescents are diagnosed with acute lymphoblastic leukemia (ALL) in the five Nordic countries, and 3% of these have central nervous system (CNS) involvement confirmed by leukemic cells in the cerebrospinal fluid (CSF) or neurological symptoms. We sought to determine the significance of neuraxis imaging in such patients.

Young patients with hematologic and lymphatic malignancies have an increased risk of hip and knee arthroplasty.

Abstract Background Skeletal complications such as osteonecrosis (ON) are potential adverse events in patients treated for cancer, especially in those treated for hematologic and lymphatic malignancies (HLMs). ON may damage the hip or knee joints and may lead to arthrosis requiring total joint arthroplasty (TJA). The aim of this study was to address the risk of TJA in patients with cancer, especially those treated for HLM, in a nationwide population-based setting. Material and methods All patients who had undergone TJA after cancer diagnosis between the years 2000 and 2012 were identified by linking the Arthroplasty Register and the Cancer Registry. Standardized incidence ratios (SIRs) of TJAs were calculated to assess whether patients with any cancer, but especially HLM, have increased risk for TJA when compared with the general population. Results In patients with HLM or other cancer, the overall SIRs were similar compared with the general population. However, in HLM patients under 50 years of age, the SIR was 7.6, and in patients under 35 years of age, it was 45.5. The corresponding SIRs in patients with other cancers were 3.6 and 6.6, respectively. The highest SIRs, including all age groups, were among patients with acute lymphoblastic leukemia (SIR = 4.5) and acute myeloid leukemia (SIR = 1.9). Discussion HLMs imply an increased risk for TJA compared with the general population. The risk is especially high in patients younger than 50 years, regardless of the type of HLM. Young patients with HLM, as well as their healthcare providers, should be aware of the highly increased risk of skeletal complications requiring TJA.

Defective WNT signaling associates with bone marrow fibrosis—a cross-sectional cohort study in a family with WNT1 osteoporosis

SummaryThis study explores bone marrow function in patients with defective WNT1 signaling. Bone marrow samples showed increased reticulin and altered granulopoiesis while overall hematopoiesis was normal. Findings did not associate with severity of osteoporosis. These observations provide new insight into the role of WNT signaling in bone marrow homeostasis.IntroductionWNT signaling regulates bone homeostasis and survival and self-renewal of hematopoietic stem cells. Aberrant activation may lead to osteoporosis and bone marrow pathology. We aimed to explore bone marrow findings in a large family with early-onset osteoporosis due to a heterozygous WNT1 mutation.MethodsWe analyzed peripheral blood samples, and bone marrow aspirates and biopsies from 10 subjects with WNT1 mutation p.C218G. One subject was previously diagnosed with idiopathic myelofibrosis and others had no previously diagnosed hematologic disorders. The findings were correlated with the skeletal phenotype, as evaluated by number of peripheral and spinal fractures and bone mineral density.ResultsPeripheral blood samples showed no abnormalities in cell counts, morphology or distributions but mild increase in platelet count. Bone marrow aspirates (from 8/10 subjects) showed mild decrease in bone marrow iron storages in 6 and variation in cell distributions in 5 subjects. Bone marrow biopsies (from 6/10 subjects) showed increased bone marrow reticulin (grade MF-2 in the myelofibrosis subject and grade MF-1 in 4 others), and an increase in overall, and a shift towards early-phase, granulopoiesis. The bone marrow findings did not associate with the severity of skeletal phenotype.ConclusionsDefective WNT signaling associates with a mild increase in bone marrow reticulin and may predispose to myelofibrosis, while overall hematopoiesis and peripheral blood values are unaltered in individuals with a WNT1 mutation. In this family with WNT1 osteoporosis, bone marrow findings were not related to the severity of osteoporosis.