The Role of Leukapheresis in the Current Management of Hyperleukocytosis in Newly Diagnosed Childhood Acute Lymphoblastic Leukemia

BACKGROUND

Hyperleukocytosis in children with acute lymphoblastic leukemia (ALL) has been associated with early morbidity and mortality. The use of leukapheresis in these children treated with contemporary therapy remains controversial.

PROCEDURE

We analyzed clinical data from patients enrolled onto frontline protocols for ALL (Total Therapy XV and XVI) between 2003 and 2014. We documented adverse events within the first 14 days in patients with a white blood cell (WBC) count ≥200 × 10(9) /l and reviewed their management.

RESULTS

Fifty-three (7.8%) of 678 consecutive pediatric patients with newly diagnosed ALL presented with hyperleukocytosis (median WBC count 393 × 10(9) /l; range 200-1,014). Two deaths in patients without initial hyperleukocytosis occurred within the first 2 weeks from diagnosis secondary to bacterial sepsis. A total of 21 (40%) patients with ALL and hyperleukocytosis developed grade 3 or 4 adverse events regardless of the use of leukapheresis (P > 0.99 and P = 0.19). Sixteen of 53 (30%) patients with ALL received low-dose chemotherapy for leukocytoreduction initially. One-third of patients received urate oxidase, and none of the patients with hyperleukocytosis required hemodialysis.

CONCLUSIONS

The early morbidity and mortality commonly associated with hyperleukocytosis in children with newly diagnosed ALL can be avoided with contemporary supportive care and conservative management possibly obviating the need for costly and potentially dangerous leukapheresis.

Quantitative associations of scalp and body subcutaneous neurofibromas with internal plexiform tumors in neurofibromatosis 1

Internal plexiform neurofibromas are a major cause of adverse outcomes in patients with neurofibromatosis 1 (NF1). We investigated the relationship of the numbers of subcutaneous neurofibromas of the scalp or body to internal plexiform tumor volume in 120 NF1 patients who had undergone whole body magnetic resonance imaging (MRI). We identified internal plexiform neurofibromas in 55% of patients, subcutaneous neurofibromas of the body in 75%, and subcutaneous neurofibromas of the scalp in 45%. The number of subcutaneous neurofibromas of the body and scalp were associated with each other (Spearman's Rho = 0.36; P < 0.001). The presence of internal tumors was associated with the presence (odds ratio [OR] = 4.38, 95% confidence interval [CI] 2.04-9.86, P < 0.001) and number (OR = 1.06 per neurofibroma, 95% CI 1.02-1.13, P < 0.001) of subcutaneous neurofibromas of the scalp. The total internal tumor volume was associated with the number of subcutaneous neurofibromas of the body (OR = 1.00086 per neurofibroma, 1.000089-1.0016, P = 0.029) and of the scalp (OR = 1.056 per neurofibroma, 1.029-1.083, P < 0.0001). Numbers of subcutaneous neurofibromas of the scalp and body are associated with internal plexiform tumor burden in NF1. Recognition of these associations may improve clinical management by helping to identify patients who will benefit most from whole body MRI and more intense clinical surveillance.

Core-shell inversion by pH modulation in dynamic covalent micelles

Dynamic covalent surfactants have been obtained by the reversible condensation of a hydrophobic aldehyde (ended by an ionic tip) with various neutral polyethylene glycol based hydrophilic amines. In water, the duality between the two hydrophilic domains (charged and neutral) leads to their segregation when the surfactants are self-assembled within micelles. Depending on the number of polyethylene glycol units, a core-shell inversion leading to a switching orientation of the ionic tips from the inside to the outside of the micelles has been demonstrated by a combination of scattering techniques. In competition experiments, when several amines of different pKas and hydrophilic polyethylene glycol chains are competing for the same aldehyde, it becomes possible to trigger this core-shell inversion by pH modulation and associated dynamic constitutional reorganization.

Benign whole body tumor volume is a risk factor for malignant peripheral nerve sheath tumors in neurofibromatosis type 1

The purpose of this study is to determine whether benign whole body tumor volume of plexiform neurofibromas (PNs) is a risk factor for malignant peripheral nerve sheath tumors (MPNST) in individuals with neurofibromatosis type 1 (NF1). Thirty-one NF1 patients with MPNSTs and 62 age- and sex-matched NF1 patients without MPNSTs, who had undergone whole body magnetic resonance imaging (MRI) were analyzed for benign whole body tumor volume. Mann-Whitney U test, Wilcoxon signed ranks test, Fisher's exact test (two-tailed), and logistic regression analysis were used for statistical analysis. Sixteen percent of all patients with MPNST did not have internal PN. The median whole body benign tumor volume in patients with PN was 352.0 mL among the MPNST group and 3.8 mL in the comparison group (p < 0.001). When the patients were stratified by age as younger or older than 30 years (median age of MPNST diagnosis), the median benign whole body tumor volume was 693.0 mL in MPNST patients and 0.0 mL in control patients younger than 30 years (p < 0.001). The mean number of PNs in MPNST patients was 2.8 (range 0-13, median 2.0) and 1.4 (range 0-13, median 1.0) in patients without MPNST (p = 0.001). The risk of MPNST development increased 0.2 % with each additional mL of benign PN volume (adjusted odds ratio [OR] = 1.002, 95 % confidence interval [CI] 1.001-1.003, p = 0.005) and was higher in patients younger than 30 years (adjusted OR = 1.007, 95 % CI 1.002-1.012, p = 0.003). Higher numbers of PNs, larger whole body benign tumor volume, and younger age are important risk factors for MPNST. We identified a subgroup of patients with MPNST without internal PN on MRI and the lack of correlation of MPNST development with tumor burden in older patients. These findings may alter our belief that all MPNSTs arise from pre-existing PNs and suggest that surveillance MRI based on clinical suspicion may be warranted in older patients, respectively.

Cardiac characterization of 16 patients with large NF1 gene deletions

The aim of this study was to characterize cardiac features of patients with neurofibromatosis 1 (NF1) and large deletions of the NF1 gene region. The study participants were 16 patients with large NF1 deletions and 16 age- and sex-matched NF1 patients without such deletions. All the patients were comprehensively characterized clinically and by echocardiography. Six of 16 NF1 deletion patients but none of 16 non-deletion NF1 patients have major cardiac abnormalities (p = 0.041). Congenital heart defects (CHDs) include mitral insufficiency in two patients and ventricular septal defect, aortic stenosis, and aortic insufficiency in one patient each. Three deletion patients have hypertrophic cardiomyopathy. Two patients have intracardiac tumors. NF1 patients without large deletions have increased left ventricular (LV) diastolic posterior wall thickness (p < 0.001) and increased intraventricular diastolic septal thickness (p = 0.001) compared with a healthy reference population without NF1, suggestive of eccentric LV hypertrophy. CHDs and other cardiovascular anomalies are more frequent among patients with large NF1 deletion and may cause serious clinical complications. Eccentric LV hypertrophy may occur in NF1 patients without whole gene deletions, but the clinical significance of this finding is uncertain. All patients with clinical suspicion for NF1 should be referred to a cardiologist for evaluation and surveillance.

Non-coding RNA ANRIL and the number of plexiform neurofibromas in patients with NF1 microdeletions

Background

Neurofibromatosis type-1 (NF1) is caused by mutations of the NF1 gene at 17q11.2. In 95% of non-founder NF1 patients, NF1 mutations are identifiable by means of a comprehensive mutation analysis. 5-10% of these patients harbour microdeletions encompassing the NF1 gene and its flanking regions. NF1 is characterised by tumours of the peripheral nerve sheaths, the pathognomonic neurofibromas. Considerable inter- and intra-familial variation in expressivity of the disease has been observed which is influenced by genetic modifiers unrelated to the constitutional NF1 mutation. The number of plexiform neurofibromas (PNF) in NF1 patients is a highly heritable genetic trait. Recently, SNP rs2151280 located within the non-coding RNA gene ANRIL at 9p21.3, was identified as being strongly associated with PNF number in a family-based association study. The T-allele of rs2151280, which correlates with reduced ANRIL expression, appears to be associated with higher PNF number. ANRIL directly binds to the SUZ12 protein, an essential component of polycomb repressive complex 2, and is required for SUZ12 occupancy of the CDKN2A/CDKN2B tumour suppressor genes as well as for their epigenetic silencing.

Methods

Here, we explored a potential association of PNF number and PNF volume with SNP rs2151280 in 29 patients with constitutional NF1 microdeletions using the exact Cochran-Armitage test for trends and the exact Mann–Whitney–Wilcoxon test. Both the PNF number and total tumour volume in these 29 NF1 patients were assessed by whole-body MRI. The NF1 microdeletions observed in these 29 patients encompassed the NF1 gene as well as its flanking regions, including the SUZ12 gene.

Results

In the 29 microdeletion patients investigated, neither the PNF number nor PNF volume was found to be associated with the T-allele of rs2151280.

Conclusion

Our findings imply that, at least in patients with NF1 microdeletions, PNF susceptibility is not associated with rs2151280. Although somatic inactivation of the NF1 wild-type allele is considered to be the PNF-initiating event in NF1 patients with intragenic mutations and patients with NF1 microdeletions, both patient groups may differ with regard to tumour progression because of the heterozygous constitutional deletion of SUZ12 present only in patients with NF1 microdeletions.

Growth dynamics of plexiform neurofibromas: a retrospective cohort study of 201 patients with neurofibromatosis 1

Background

To examine the natural growth dynamics of internal plexiform neurofibromas (PNs) in patients with neurofibromatosis 1 (NF1).

Methods

Two hundred and one NF1 patients underwent whole body MRI (WBMRI). Tumour burden was estimated volumetrically. Non-parametric Spearman’s rho correlation coefficients were used to analyse the relationship of growth rate to tumour volume and age. Chi-squared and Mann–Whitney U tests were used for analysing the association of tumour occurrence with sex or age. Chi-squared tests were used to analyse the association of tumour growth with age group.

Results

Seventy-one of 171 patients with serial WBMRI exams had internal PNs (median follow up 2.2 years [1.1 to 4.9 years]). Median whole body tumour volume was 86.4 mL [5.2 to 5878.5 mL]) with a median growth rate of 3.7%/year (−13.4 to 111%/year) that correlated with larger whole body tumour volume (P<0.001) and lower age (P=0.004). No new PNs developed in 273.0 patient-years among patients without tumours. Rate of new tumour development among patients with PNs was 0.6%/year (95% confidence interval 0.02 to 3.4%). Twenty-seven (13.5%) tumours increased significantly and were more frequent among children (P<0.001). Growth rate of tumours was inversely correlated with age (Spearman’s rho=−0.330, P<0.001). Seventy-one (35.5%) tumours had smaller volumes on follow up (median −3.4%/year [−0.07% to −35.9%/year]).

Conclusion

Children with NF1 and internal PNs are at risk for tumour growth. Most PNs grow slowly or not at all, and some decrease in size. New tumours are infrequent in NF1 patients with PNs and unlikely in patients without PNs.

Relationship between whole-body tumor burden and quality of life in patients with neurofibromatosis

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Background: NF1, NF2, and schwannomatosis are a group of related genetic disorders in which affected individuals share the predisposition to develop multiple nerve sheath tumors. While previous studies have investigated the relationship between cutaneous tumor burden and quality of life, the relation between internal tumors and quality of life is unknown. Methods: As part of an IRB-approved research study, we performed whole-body MRI and administered the short form (SF)-36 to 245 adult subjects with NF. The number and location of internal nerve sheath tumors in each patient was identified by a board-certified radiologist and tumor volume was calculated using semi-automated volumetric analysis. One sample t-tests were used to compare subjects’ SF-36 scores to general population means. Independent linear regression analyses controlling for age and gender effects were used to relate whole-body tumor count, volume, and distribution (via Gini coefficient) to each domain of the SF-36. Results: 245 patients (142 with NF1, 53 with NF2, 50 with schwannomatosis) completed the study. On the SF-36, subjects with NF1 showed reduced quality of life in the physical role, emotional role, and mental health domains compared to the normal population (p<0.05). Subjects with NF2 showed reductions in the physical functioning, physical role, general health, and social functioning domains while subjects with schwannomatosis showed reductions in the physical role and bodily pain domains (p<0.05). In linear regression analysis, increased tumor number, increased tumor volume, and decreased Gini coefficient were correlated with decreased physical functioning in patients with NF2 (p<0.01). There was also a trend for increasing tumor volume to be correlated with decreased physical role and increased bodily pain in patients with NF1 and with increased bodily pain in patients with schwannomatosis (p<0.10). Conclusions: In our multi-institutional cohort, patients with all forms of neurofibromatosis show selected deficits in quality of life. Internal tumor burden does not correlate with these deficits, with the exception of physical function in NF2 patients.

Quantitative assessment of whole-body tumor burden in adult patients with neurofibromatosis

PURPOSE

Patients with neurofibromatosis 1 (NF1), NF2, and schwannomatosis are at risk for multiple nerve sheath tumors and premature mortality. Traditional magnetic resonance imaging (MRI) has limited ability to assess disease burden accurately. The aim of this study was to establish an international cohort of patients with quantified whole-body internal tumor burden and to correlate tumor burden with clinical features of disease.

METHODS

We determined the number, volume, and distribution of internal nerve sheath tumors in patients using whole-body MRI (WBMRI) and three-dimensional computerized volumetry. We quantified the distribution of tumor volume across body regions and used unsupervised cluster analysis to group patients based on tumor distribution. We correlated the presence and volume of internal tumors with disease-related and demographic factors.

RESULTS

WBMRI identified 1286 tumors in 145/247 patients (59%). Schwannomatosis patients had the highest prevalence of tumors (P = 0.03), but NF1 patients had the highest median tumor volume (P = 0.02). Tumor volume was unevenly distributed across body regions with overrepresentation of the head/neck and pelvis. Risk factors for internal nerve sheath tumors included decreasing numbers of café-au-lait macules in NF1 patients (P = 0.003) and history of skeletal abnormalities in NF2 patients (P = 0.09). Risk factors for higher tumor volume included female gender (P = 0.05) and increasing subcutaneous neurofibromas (P = 0.03) in NF1 patients, absence of cutaneous schwannomas in NF2 patients (P = 0.06), and increasing age in schwannomatosis patients (p = 0.10).

CONCLUSION

WBMRI provides a comprehensive phenotype of neurofibromatosis patients, identifies distinct anatomic subgroups, and provides the basis for investigating molecular biomarkers that correlate with unique disease manifestations.

Internal tumor burden in neurofibromatosis Type I patients with large NF1 deletions

Neurofibromatosis Type 1 (NF1) is a frequent tumor suppressor gene disorder characterized by multiple benign tumors and high risk of malignancy. Internal tumor burden is a major disease-associated manifestation and can be most adequately assessed by magnetic resonance imaging of the whole body. Approximately 5% of NF1 patients have constitutional large NF1-deletions that are generally associated with more severe clinical manifestations. Here, we investigated whether these deletion patients also have more and/or larger internal tumors by assessing internal tumors and their total volume (exclusive of cutaneous and subcutaneous) in 38 NF1 deletion patients (including eight mosaic cases) and 114 age- and gender-matched NF1 patients without deletions. The incidence of internal tumors was significantly lower in mosaic deletion patients (1/8 = 13%) but did not differ between the 30 nonmosaic deletion patients and the 90 age- and gender-matched NF1 patients without large deletions used as controls. Neither the number nor the total volume of tumors per patient differed significantly between the latter two groups. However, extremely high tumor burden (>3,000 ml) was significantly more frequent among nonmosaic NF1 deletion patients than among NF1 patients without large deletions (13% vs. 1%, P = 0.014). Thus, as a group, patients with NF1 deletions do not exhibit a significantly higher internal tumor burden than NF1 patients without such deletions. However, deletion patients can frequently have extremely large internal tumors and thus demand special attention.

Delineation of the clinical phenotype associated with non-mosaic type-2 NF1 deletions: two case reports

INTRODUCTION

Large deletions of the NF1 gene and its flanking regions are frequently associated with a severe clinical manifestation. Different types of gross NF1 deletion have been identified that are distinguishable both by their size and the number of genes included within the deleted regions. Type-1 NF1 deletions encompass 1.4 Mb and include 14 genes, whereas the much less common type-2 NF1 deletions span 1.2 Mb and contain 13 genes. Genotype-phenotype correlations in patients with large NF1 deletions are likely to be influenced by the nature and number of the genes deleted in addition to the NF1 gene. Whereas the clinical phenotype associated with type-1 NF1 deletions has been well documented, the detailed clinical characterization of patients with non-mosaic type-2 NF1 deletions has not so far been reported.

CASE PRESENTATION

In the present report we characterized two Caucasian European patients with non-mosaic (germline) type-2 NF1 deletions. Our first patient was a 13-year-old girl with dysmorphic facial features, mild developmental delay, large hands and feet, hyperflexibility of the joints, macrocephaly and T2 hyperintensities in the brain. A whole-body magnetic resonance imaging scan indicated two internal plexiform neurofibromas. Our second patient was an 18-year-old man who exhibited dysmorphic facial features, developmental delay, learning disability, large hands and feet, hyperflexibility of the joints, macrocephaly and a very high subcutaneous and internal tumor load as measured volumetrically on whole-body magnetic resonance imaging scans. At the age of 18 years, he developed a malignant peripheral nerve sheath tumor and died from secondary complications. Both our patients exhibited cardiovascular malformations.

CONCLUSIONS

Our two patients with non-mosaic type-2 NF1 deletions exhibited clinical features that have been reported in individuals with germline type-1 NF1 deletions. Therefore, a severe disease manifestation is not confined to only patients with type-1 NF1 deletions but may also occur in individuals with type-2 NF1 deletions. Our findings support the concept of an NF1 microdeletion syndrome with severe clinical manifestation that is caused by type-1 as well as type-2 NF1 deletions.

Plexiform neurofibromas in children with neurofibromatosis type 1: frequency and associated clinical deficits

OBJECTIVES

To define the frequency and clinical features of plexiform neurofibromas (PN) in children with neurofibromatosis type 1.

STUDY DESIGN

Sixty-five children received whole-body magnetic resonance imaging (MRI) and clinical-neurologic examination. Tumor sizes were calculated volumetrically with the program MedX v3.42. χ(2) test, Fisher exact test, t test, and Spearman rank correlation were used for statistical analysis.

RESULTS

Seventy-three tumors were detected in 37 of these 65 children. The mean volume of the tumors was 145.4 mL or 4.8 mL/kg body weight. Eighteen of the 73 PNs caused clinical deficits in 17 children, and the other 56 PNs in 20 children were asymptomatic. Symptomatic tumors were larger than asymptomatic ones (9.6 vs 3.3 mL/kg body weight; P = .01). However, in certain body regions, for example, the head, small tumors also caused clinical deficits. Ten of 18 children ≥11.5 years (median age of the 37 children with PNs) had symptomatic PNs compared with 7 of 19 who were <11.5 years (P = .25).

CONCLUSION

PNs cause clinical deficits in young children. Early detection and regular MRI monitoring help to estimate growth and possible upcoming complications, and are thus beneficial for optimizing treatment and management.

MIA is a potential biomarker for tumour load in neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is a frequent genetic disease characterized by multiple benign tumours with increased risk for malignancy. There is currently no biomarker for tumour load in NF1 patients.

METHODS

In situ hybridization and quantitative real-time polymerase reaction were applied to investigate expression of cartilage-specific genes in mice bearing conditional inactivation of NF1 in the developing limbs. These mice do not develop tumours but recapitulate aspects of NF1 bone dysplasia, including deregulation of cartilage differentiation. It has been recently shown that NF1 tumours require for their growth the master regulator of cartilage differentiation SOX9. We thus hypothesized that some of the cartilage-specific genes deregulated in an Nf1Prx1 mouse model might prove to be relevant biomarkers of NF1 tumours. We tested this hypothesis by analyzing expression of the SOX9 target gene product melanoma-inhibitory activity/cd-rap (MIA) in tumour and serum samples of NF1 patients.

RESULTS

Increased expression of Mia was found in Nf1-deficient cartilage in mice. In humans, MIA was expressed in all NF1-related tumours and its serum levels were significantly higher in NF1 patients than in healthy controls. Among NF1 patients, MIA serum levels were significantly higher in those with plexiform neurofibromas and in those with large number of cutaneous (> 1,000) or subcutaneous (> 100) neurofibromas than in patients without such tumours. Most notably, MIA serum levels correlated significantly with internal tumour burden.

CONCLUSIONS

MIA is a potential serum biomarker of tumour load in NF1 patients which could be useful in following the disease course and monitoring the efficacy of therapies.

Cancer stem cell-like cells derived from malignant peripheral nerve sheath tumors

This study aims to examine whether or not cancer stem cells exist in malignant peripheral nerve sheath tumors (MPNST). Cells of established lines, primary cultures and freshly dissected tumors were cultured in serum free conditions supplemented with epidermal and fibroblast growth factors. From one established human MPNST cell line, S462, cells meeting the criteria for cancer stem cells were isolated. Clonal spheres were obtained, which could be passaged multiple times. Enrichment of stem cell-like cells in these spheres was also supported by increased expression of stem cell markers such as CD133, Oct4, Nestin and NGFR, and decreased expression of mature cell markers such as CD90 and NCAM. Furthermore, cells of these clonal S462 spheres differentiated into Schwann cells, smooth muscle/fibroblast and neurons-like cells under specific differentiation-inducing cultural conditions. Finally, subcutaneous injection of the spheres into immunodeficient nude mice led to tumor formation at a higher rate compared to the parental adherent cells (66% versus 10% at 2.5×10⁵). These results provide evidence for the existence of cancer stem cell-like cells in malignant peripheral nerve sheath tumors.