Janice Kohler

Constitutional 11p15 abnormalities, including heritable imprinting center mutations, cause nonsyndromic Wilms tumor

Constitutional abnormalities at the imprinted 11p15 growth regulatory region cause syndromes characterized by disordered growth, some of which include a risk of Wilms tumor. We explored their possible contribution to nonsyndromic Wilms tumor and identified constitutional 11p15 abnormalities in genomic lymphocyte DNA from 13 of 437 individuals (3%) with sporadic Wilms tumor without features of growth disorders, including 12% of bilateral cases (P = 0.001) and in one familial Wilms tumor pedigree. No abnormality was detected in 220 controls (P = 0.006). Abnormalities identified included H19 DMR epimutations, uniparental disomy 11p15 and H19 DMR imprinting center mutations (one microinsertion and one microdeletion), thus identifying microinsertion as a new class of imprinting center mutation. Our data identify constitutional 11p15 defects as one of the most common known causes of Wilms tumor, provide mechanistic insights into imprinting disruption and reveal clinically important epigenotype-phenotype associations. The impact on clinical management dictates that constitutional 11p15 analysis should be considered in all individuals with Wilms tumor.

A genome-wide association study identifies susceptibility loci for Wilms tumor

Wilms tumor is the most common renal malignancy of childhood. To identify common variants that confer susceptibility to Wilms tumor, we conducted a genome-wide association study in 757 individuals with Wilms tumor (cases) and 1,879 controls. We evaluated ten SNPs in regions significantly associated at P < 5 × 10−5 in two independent replication series from the UK (769 cases and 2,814 controls) and the United States (719 cases and 1,037 controls). We identified clear significant associations at 2p24 (rs3755132, P = 1.03 × 10−14; rs807624, P = 1.32 × 10−14) and 11q14 (rs790356, P = 4.25 × 10−15). Both regions contain genes that are plausibly related to Wilms tumorigenesis. We also identified candidate association signals at 5q14, 22q12 and Xp22.

Dose Finding Study for the Use of Subcutaneous Recombinant Interleukin-2 to Augment Natural Killer Cell Numbers in an Outpatient Setting for Stage 4 Neuroblastoma After Megatherapy and Autologous Stem-Cell Reinfusion

PURPOSE To establish a safe dose of subcutaneous (SC) recombinant interleukin 2 (rIL-2) in an outpatient setting for children with stage 4 neuroblastoma after megatherapy (MGT) and autologous stem-cell reinfusion (ASCR) that is able to sustain an increase of natural-killer cells (NKCs) above the level previously reported for immunomodulatory potency. PATIENTS AND METHODS Between August 1997 and November 2000, 33 patients with stage 4 neuroblastoma entered the study from six countries after receiving MGT/ASCR according to national protocols. Dose levels of 3, 6, and 9 × 10(6) U rIL-2/m(2) were given SC in six 5-day cycles every 2 weeks. RESULTS Median age at registration was 4.1 years (range, 1.8 to 7.4). Median observation time was 5 years (range, 4 to 9.8). Increase of NKCs was achieved in 89% of courses, with more than 100% increase over baseline and/or more than 1,000 NKCs/μL in 58%. On the basis of outpatient dose-limiting toxicity at dose level 3, dose level 2 was chosen for the confirmation stage. At dose level 2, the median increase in absolute NKCs was 1,180 cells/μL for all 83 cycles, corresponding to a median relative NKC increase over baseline of 711%. Fever was frequent but controllable with adequate supportive care; 6.5% of patients were hospitalized. Localized pain was moderate and acceptable. Event-free and overall survival rates at 5 years were 45% (± 9 standard deviation [SD]) and 48% (± 9 SD), respectively. CONCLUSION The low toxicity profile and ability to sustain an increase in NKCs of IL-2 at 6 × 10(6) U/m(2) SC allows its integration in an outpatient setting.

Late relapse and prognosis for neuroblastoma patients surviving 5 years or more: A report from the European Neuroblastoma Study Group “Survey”

BACKGROUND AND PROCEDURE Most deaths from neuroblastoma occur within 2 years of diagnosis but there have been several anecdotal reports of relapse and death after much longer periods of follow up. In order to investigate and quantify the risk of late events we analysed data for patients registered with the European Neuroblastoma Study Group between 1982 and 1990. Out of a total of 1,277 children registered, 427 were alive with follow-up beyond 5 years from diagnosis (median follow-up of 8.8 years, range 5-14 years). Of these 406 were in remission with no prior recurrence, 16 were in remission having experienced a relapse prior to 5 years, and 5 were alive with progressive disease. RESULTS For the 406 patients in remission with no prior relapse the 10 year progression free survival (PFS) was 96% (CI 94-98). For those aged over 1 year with stage 4 disease at diagnosis 10 year PFS was 88% (CI 79-96) compared to 98% (CI 97-99) for other patients combined, P< 0.001. In a multivariate analysis of all 422 patients in remission at 5 years, significant risk factors for subsequent relapse were age > 1 yr with stage 4 disease at diagnosis (relative risk 10.5, P < 0.001) and prior relapse (RR 4.2, P= 0.01). CONCLUSIONS The results of this study emphasise the importance of longterm follow-up of patients and the need for late monitoring of clinical trials in children with neuroblastoma. They also provide a baseline for comparison with future and hopefully more effective treatment programmes.

Effectiveness of HB2 (anti-CD7)--saporin immunotoxin in an in vivo model of human T-cell leukaemia developed in severe combined immunodeficient mice.

The transplantation of the human T-cell acute lymphoblastic leukaemia (T-ALL) cell line HSB-2 into severe combined immunodeficient (SCID) mice was found to produce a disseminated pattern of leukaemia similar to that seen in man. The intravenous injection of 10(7) HSB-2 cells was associated with a universally fatal leukaemia. Histopathological examination of animals revealed the spread of leukaemia initially from bone marrow to involve all major organs including the meninges. An immunotoxin (HB2-Sap) was constructed by conjugating the anti-CD7 MAb HB2 to the ribosome-inactivating protein saporin. An in vitro protein synthesis inhibition assay revealed specific delivery of HB2-Sap immunotoxin (IT) to CD7+ HSB-2 target cells with an IC50 of 4.5 pM. When SCID mice were injected with 10(6) HSB-2 cells and then treated 8 days later with a single intravenous dose of 10 micrograms of immunotoxin there was a significant therapeutic effect evidenced by the numbers of animals surviving in the therapy group compared with untreated controls (chi 2 = 5.348, P = 0.021). These results demonstrate the useful application of human leukaemia xenografts in SCID mice and the potential therapeutic effect of an anti-CD7 immunotoxin in human T-ALL.

Immunotherapy for neuroblastoma: Turning promise into reality

Neuroblastoma is one of the commonest and most aggressive paediatric malignancies. The majority of children present with metastatic disease for which long‐term survival remains poor despite intensive multi‐modal therapies. Toxicity from current treatment regimes is already significant, and there is little room to further intensify therapy. Alternative treatment strategies are therefore needed in order to improve survival. Immunotherapy is an attractive therapeutic option for these children as it potentially offers a much more specific and less toxic treatment than conventional therapies. This review discusses the different immunotherapy strategies that may be useful in neuroblastoma, their advantages and disadvantages and the challenges that need to be overcome to successfully use them clinically. Pediatr Blood Cancer 2009;53:931–940.

Response to N7 induction chemotherapy in children more than one year of age diagnosed with metastatic neuroblastoma treated in UKCCSG centers

The highest reported metastatic response rate to induction chemotherapy in patients with neuroblastoma has been achieved by Kushner et al. [Kushner et al.: J Clin Oncol 12:2607–2613,1994; Cheung et al.: Med Pediatr Oncol 36: 227–230, 2001; Kushner et al.: J Clin Oncol 22:4888‐4892, 2004] using their N6 and subsequently N7 protocols. This N7 induction was adopted by UKCCSG for new patients in 1999.

Superior Sagittal Sinus Thrombosis Complicating Maintenance Treatment for Acute Lymphoblastic Leukemia

A girl with acute lymphoblastic leukemia in remission had two seizures during the maintenance phase of her treatment. Magnetic resonance imaging with angiography identified a superior sagittal sinus thrombosis as the likely explanation for her symptoms. Possible causes are considered, and previous reports of the neurotoxicity of agents used in the treatment of leukemia are reviewed.

Influence of segmental chromosome abnormalities on survival in children over the age of 12 months with unresectable localised peripheral neuroblastic tumours without MYCN amplification.

Background:The prognostic impact of segmental chromosome alterations (SCAs) in children older than 1 year, diagnosed with localised unresectable neuroblastoma (NB) without MYCN amplification enrolled in the European Unresectable Neuroblastoma (EUNB) protocol is still to be clarified, while, for other group of patients, the presence of SCAs is associated with poor prognosis.Methods:To understand the role of SCAs we performed multilocus/pangenomic analysis of 98 tumour samples from patients enrolled in the EUNB protocol.Results:Age at diagnosis was categorised into two groups using 18 months as the age cutoff. Significant difference in the presence of SCAs was seen in tumours of patients between 12 and 18 months and over 18 months of age at diagnosis, respectively (P=0.04). A significant correlation (P=0.03) was observed between number of SCAs per tumour and age. Event-free (EFS) and overall survival (OS) were calculated in both age groups, according to both the presence and number of SCAs. In older patients, a poorer survival was associated with the presence of SCAs (EFS=46% vs 75%, P=0.023; OS=66.8% vs 100%, P=0.003). Moreover, OS of older patients inversely correlated with number of SCAs (P=0.002). Finally, SCAs provided additional prognostic information beyond histoprognosis, as their presence was associated with poorer OS in patients over 18 months with unfavourable International Neuroblastoma Pathology Classification (INPC) histopathology (P=0.018).Conclusions:The presence of SCAs is a negative prognostic marker that impairs outcome of patients over the age of 18 months with localised unresectable NB without MYCN amplification, especially when more than one SCA is present. Moreover, in older patients with unfavourable INPC tumour histoprognosis, the presence of SCAs significantly affects OS.

An Immunohistochemical Study of Testicular Biopsies in Childhood Acute Lymphoblastic Leukemia: Reactivity of Normal Testicular Components and Leukemic Infiltrates

We performed an immunohistochemical analysis of frozen sections from testicular biopsies from 23 children with acute lymphoblastic leukemia. Eleven cases were infiltrated by leukemia. Tumor cells were immunostained by a panel of antibodies that identified CD10, CD43, CD19, CD3, CD7, and MHC class I and II. The immunoreactivity of normal testicular components was also studied. Normal testis showed no CD10 reactivity. Wide variation in the number of stromal macrophages identified by CD11c was found. Transferrin receptor (CD71) was expressed by some stromal macrophages, by seminiferous tubules, and by Leydig cells. B lymphocytes were absent from the testicular stroma but small numbers of T lymphocytes were consistently present. MHC class I and II were expressed by most stromal cells but not by seminiferous tubules.