Long-term kidney function in children with Wilms tumour and constitutional WT1 pathogenic variant.

BACKGROUND: Wilms tumour (WT) survivors, especially patients with associated syndromes or genitourinary anomalies due to constitutional WT1 pathogenic variant, have increased risk of kidney failure. We describe the long-term kidney function in children with WT and WT1 pathogenic variant to inform the surgical strategy and oncological management of such complex children. METHODS: Retrospective analysis of patients with WT and constitutional WT1 pathogenic variant treated at a single centre between 1993 and 2016, reviewing genotype, phenotype, tumour histology, laterality, treatment, patient survival, and kidney outcome. RESULTS: We identified 25 patients (60% male, median age at diagnosis 14 months, range 4-74 months) with WT1 deletion (4), missense (2), nonsense (8), frameshift (7), or splice site (4) pathogenic variant. Thirteen (52%) had bilateral disease, 3 (12%) had WT-aniridia, 1 had incomplete Denys-Drash syndrome, 11 (44%) had genitourinary malformation, and 10 (40%) had no phenotypic anomalies. Patient survival was 100% and 3 patients were in remission after relapse at median follow-up of 9 years. Seven patients (28%) commenced chronic dialysis of which 3 were after bilateral nephrectomies. The overall kidney survival for this cohort as mean time to start of dialysis was 13.38 years (95% CI: 10.3-16.4), where 7 patients experienced kidney failure at a median of 5.6 years. All of these 7 patients were subsequently transplanted. In addition, 2 patients have stage III and stage IV chronic kidney disease and 12 patients have albuminuria and/or treatment with ACE inhibitors. Four patients (3 frameshift; 1 WT1 deletion) had normal blood pressure and kidney function without proteinuria at follow-up from 1.5 to 12 years. CONCLUSIONS: Despite the known high risk of kidney disease in patients with WT and constitutional WT1 pathogenic variant, nearly two-thirds of patients had sustained native kidney function, suggesting that nephron-sparing surgery (NSS) should be attempted when possible without compromising oncological risk. Larger international studies are needed for accurate assessment of WT1genotype-kidney function phenotype correlation.

Risk of Adverse Health and Social Outcomes Up to 50 Years After Wilms Tumor: The British Childhood Cancer Survivor Study.

PURPOSE: Survivors of Wilms tumor (WT) are at risk for adverse health and social outcomes but risks beyond 30 years from diagnosis remain uncertain. We investigated the risks of adverse outcomes among 5-year survivors of WT, in particular, those between 30 and 50 years from diagnosis. PATIENTS AND METHODS: The British Childhood Cancer Survivor Study includes 1,441 5-year survivors of WT. We investigated cause-specific mortality, risk of subsequent primary neoplasms (SPNs), and, for those who completed a questionnaire, the extent of smoking and drinking, educational achievement, health status, and health service use compared with the general population. RESULTS: Cumulative risk of death from all causes, excluding recurrence, increased substantially from 5.4% to 22.7% at 30 years and 50 years, respectively, after WT diagnosis-75% of excess deaths beyond 30 years from diagnosis were attributable to SPNs (50%) and cardiac diseases (25%). Digestive cancer, most frequently bowel, accounted for 41% of excess cancers beyond 30 years. CONCLUSION: Between 30 and 50 years from diagnosis, survivors of WT are at a substantially increased risk of premature mortality, and 75% of excess deaths were accounted for by SPNs and cardiac diseases. Radiotherapy exposure was a risk factor for both outcomes. The proportion of patients with WT who are exposed to radiotherapy has reduced substantially in recent decades because of initiatives such as the SIOP WT 2001 clinical trial, which sought to reduce late effects; however, the majority of current survivors, who are at least 30 years from diagnosis, received radiotherapy. Surveillance of this group should focus on SPNs, in particular, bowel and breast cancers, and cardiac conditions.

Long-term risks of subsequent primary neoplasms among survivors of childhood cancer.

CONTEXT: Survivors of childhood cancer are at excess risk of developing subsequent primary neoplasms but the long-term risks are uncertain. OBJECTIVES: To investigate long-term risks of subsequent primary neoplasms in survivors of childhood cancer, to identify the types that contribute most to long-term excess risk, and to identify subgroups of survivors at substantially increased risk of particular subsequent primary neoplasms that may require specific interventions. DESIGN, SETTING, AND PARTICIPANTS: British Childhood Cancer Survivor Study--a population-based cohort of 17,981 5-year survivors of childhood cancer diagnosed with cancer at younger than 15 years between 1940 and 1991 in Great Britain, followed up through December 2006. MAIN OUTCOME MEASURES: Standardized incidence ratios (SIRs), absolute excess risks (AERs), and cumulative incidence of subsequent primary neoplasms. RESULTS: After a median follow-up time of 24.3 years (mean = 25.6 years), 1354 subsequent primary neoplasms were ascertained; the most frequently observed being central nervous system (n = 344), nonmelanoma skin cancer (n = 278), digestive (n = 105), genitourinary (n = 100), breast (n = 97), and bone (n = 94). The overall SIR was 4 times more than expected (SIR, 3.9; 95% confidence interval [CI], 3.6-4.2; AER, 16.8 per 10,000 person-years). The AER at older than 40 years was highest for digestive and genitourinary subsequent primary neoplasms (AER, 5.9 [95% CI, 2.5-9.3]; and AER, 6.0 [95%CI, 2.3-9.6] per 10,000 person-years, respectively); 36% of the total AER was attributable to these 2 subsequent primary neoplasm sites. The cumulative incidence of colorectal cancer for survivors treated with direct abdominopelvic irradiation was 1.4% (95% CI, 0.7%-2.6%) by age 50 years, comparable with the 1.2% risk in individuals with at least 2 first-degree relatives affected by colorectal cancer. CONCLUSION: Among a cohort of British childhood cancer survivors, the greatest excess risk associated with subsequent primary neoplasms at older than 40 years was for digestive and genitourinary neoplasms.

DICER1 syndrome: clarifying the diagnosis, clinical features and management implications of a pleiotropic tumour predisposition syndrome.

BACKGROUND: Constitutional DICER1 mutations were recently reported to cause familial pleuropulmonary blastoma (PPB). AIM: To investigate the contribution and phenotypic spectrum of constitutional and somatic DICER1 mutations to cancer. METHODS AND RESULTS: The authors sequenced DICER1 in constitutional DNA from 823 unrelated patients with a variety of tumours and in 781 cancer cell lines. Constitutional DICER1 mutations were identified in 19 families including 11/14 with PPB, 2/3 with cystic nephroma, 4/7 with ovarian Sertoli-Leydig-type tumours, 1/243 with Wilms tumour (this patient also had a Sertoli-Leydig tumour), 1/1 with intraocular medulloepithelioma (this patient also had PPB), 1/86 with medulloblastoma/infratentorial primitive neuroectodermal tumour, and 1/172 with germ cell tumour. The inheritance was investigated in 17 families. DICER1 mutations were identified in 25 relatives: 17 were unaffected, one mother had ovarian Sertoli-Leydig tumour, one half-sibling had cystic nephroma, and six relatives had non-toxic thyroid cysts/goitre. Analysis of eight tumours from DICER1 mutation-positive patients showed universal retention of the wild-type allele. DICER1 truncating mutations were identified in 4/781 cancer cell lines; all were in microsatellite unstable lines and therefore unlikely to be driver mutations. CONCLUSION: Constitutional DICER1 haploinsufficiency predisposes to a broad range of tumours, making a substantial contribution to PPB, cystic nephroma and ovarian Sertoli-Leydig tumours, but a smaller contribution to other tumours. Most mutation carriers are unaffected, indicating that tumour risk is modest. The authors define the clinical contexts in which DICER1 mutation testing should be considered, the associated tumour risks, and the implications for at-risk individuals. They have termed this condition 'DICER1 syndrome'. ACCESSION NUMBERS: The cDNA Genbank accession number for the DICER1 sequence reported in this paper is NM_030621.2.

Safety, pharmacokinetics, and preliminary activity of the anti-IGF-1R antibody figitumumab (CP-751,871) in patients with sarcoma and Ewing's sarcoma: a phase 1 expansion cohort study.

BACKGROUND: Figitumumab is a fully human IgG2 monoclonal antibody targeting the insulin-like growth-factor-1 receptor (IGF-1R). Preclinical data suggest a dependence on insulin-like growth-factor signalling for sarcoma subtypes, including Ewing's sarcoma, and early reports show antitumour activity of IGF-1R-targeting drugs in these diseases. METHODS: Between January, 2006, and August, 2008, patients with refractory, advanced sarcomas received figitumumab (20 mg/kg) in two single-stage expansion cohorts within a solid-tumour phase 1 trial. The first cohort (n=15) included patients with multiple sarcoma subtypes, age 18 years or older, and the second cohort (n=14) consisted of patients with refractory Ewing's sarcoma, age 9 years or older. The primary endpoint was to assess the safety and tolerability of figitumumab. Secondary endpoints included pharmacokinetic profiling and preliminary antitumour activity (best response by Response Evaluation Criteria in Solid Tumours [RECIST]) in evaluable patients who received at least one dose of medication. This study is registered with ClinicalTrials.gov, number NCT00474760. FINDINGS: 29 patients, 16 of whom had Ewing's sarcoma, were enrolled and received a total of 177 cycles of treatment (median 2, mean 6.1, range 1-24). Grade 3 deep venous thrombosis, grade 3 back pain, and grade 3 vomiting were each noted once in individual patients; one patient had grade 3 increases in aspartate aminotransferase and gammaglutamyltransferase concentrations. This patient also had grade 4 increases in alanine aminotransferase concentrations. The only other grade 4 adverse event was raised concentrations of uric acid, noted in one patient. Pharmacokinetics were comparable between patients with sarcoma and those with other solid tumours. 28 patients were assessed for response; two patients, both with Ewing's sarcoma, had objective responses (one complete response and one partial response) and eight patients had disease stabilisation (six with Ewing's sarcoma, one with synovial sarcoma, and one with fibrosarcoma) lasting 4 months or longer. INTERPRETATION: Figitumumab is well tolerated and has antitumour activity in Ewing's sarcoma, warranting further investigation in this disease. FUNDING: Pfizer Global Research and Development.

Medulloblastoma, acute myelocytic leukemia and colonic carcinomas in a child with biallelic MSH6 mutations.

Background A 13-year-old girl presented with rectal bleeding and was found to have two colonic carcinomas (stage Dukes' C) and multiple colonic polyps. At the age of 7 years she had widespread hyperpigmented and hypopigmented skin lesions, and had developed medulloblastoma, which was treated with chemotherapy and craniospinal irradiation. At the age of 10 years she had developed acute myelocytic leukemia, M5. She was treated with chemotherapy including sibling bone marrow transplant with busulfan/cyclophosphamide conditioning. A three-generation family history identified no relatives with colonic carcinomas or polyposis. Investigations Immunohistochemical analysis was performed on a sample of colonic adenoma. Staining for MLH1 and MSH2 was normal but was absent for MSH6. Direct sequencing of MSH6 was performed in the proband and both parents. Diagnosis Constitutional biallelic mutations in the mismatch repair gene MSH6 were identified in the proband. Both parents are carriers of one mutation. This is the first individual with biallelic MSH6 mutations reported with either medulloblastoma or acute myelocytic leukemia. Management Cascade genetic testing and colonoscopic screening for colorectal carcinoma has been offered to relatives carrying one mutation. The proband underwent panproctocolectomy and received adjuvant capecitabine. Identification of constitutional biallelic mismatch repair gene mutations allows the avoidance of chemotherapeutic agents likely to be ineffective and mutagenic in the context of the underlying mismatch repair deficiency. It is important to consider this diagnosis in children presenting with malignancy and abnormal skin pigmentation, even in the absence of a strong family history of tumors.

Comparative genomic hybridization and BUB1B mutation analyses in childhood cancers associated with mosaic variegated aneuploidy syndrome.

We previously demonstrated that constitutional BUB1B mutations cause mosaic variegated aneuploidy, a condition characterized by constitutional aneuploidies and childhood cancer predisposition. To further investigate the role of BUB1B in cancer predisposition we performed comparative genomic hybridization analysis in an embryonal rhabdomyosarcoma from an MVA case with biallelic BUB1B mutations, revealing aneuploidies typical of sporadic E-RMS, with gain of chromosomes 3, 8, 13 and loss of chromosomes 9, 14, X. To investigate whether somatic BUB1B mutations occur in sporadic childhood cancers we screened 30 Wilms tumours, 10 acute lymphoblastic leukemias, nine rhabdomyosarcomas and 11 rhabdomyosarcoma cell lines for BUB1B mutations. We identified seven exonic and six intronic variants. Six of the exonic variants were synonymous and one resulted in a non-synonymous conservative missense alteration that was also present in a control. These data suggest that the genetic progression in rhabdomyosarcoma from MVA and non-MVA cases may be similar, but that somatic BUB1B mutations are unlikely to be common in sporadic childhood cancers known to be associated with MVA.

Disruption of WT1 gene expression and exon 5 splicing following cytotoxic drug treatment: antisense down-regulation of exon 5 alters target gene expression and inhibits cell survival.

Deregulated expression of the Wilms' tumor gene (WT1) has been implicated in the maintenance of a malignant phenotype in leukemias and a wide range of solid tumors through interference with normal signaling in differentiation and apoptotic pathways. Expression of high levels of WT1 is associated with poor prognosis in leukemias and breast cancer. Using real-time (Taqman) reverse transcription-PCR and RNase protection assay, we have shown up-regulation of WT1 expression following cytotoxic treatment of cells exhibiting drug resistance, a phenomenon not seen in sensitive cells. WT1 is subject to alternative splicing involving exon 5 and three amino acids (KTS) at the end of exon 9, producing four major isoforms. Exon 5 splicing was disrupted in all cell lines studied following a cytotoxic insult probably due to increased exon 5 skipping. Disruption of exon 5 splicing may be a proapoptotic signal because specific targeting of WT1 exon 5-containing transcripts using a nuclease-resistant antisense oligonucleotide (ASO) killed HL60 leukemia cells, which were resistant to an ASO targeting all four alternatively spliced transcripts simultaneously. K562 cells were sensitive to both target-specific ASOs. Gene expression profiling following treatment with WT1 exon 5-targeted antisense showed up-regulation of the known WT1 target gene, thrombospondin 1, in HL60 cells, which correlated with cell death. In addition, novel potential WT1 target genes were identified in each cell line. These studies highlight a new layer of complexity in the regulation and function of the WT1 gene product and suggest that antisense directed to WT1 exon 5 might have therapeutic potential.