Constitutional interstitial deletion of 11p11 and pericentric inversion of chromosome 9 in a patient with Wiedemann-Beckwith syndrome and hepatoblastoma

Occurrence of Hepatoblastomas in Patients with Beckwith-Wiedemann Spectrum (BWSp)

Patients with Beckwith-Wiedemann syndrome (BWS), an epigenetic imprinting disorder involving alterations in genes at the 11p15 chromosomal location, are predisposed to develop hepatoblastomas (HBs), which are rare embryonal liver tumors. Tumors can develop after a BWS diagnosis or, conversely, can be the presenting feature leading to a subsequent diagnosis. While HBs are the cardinal tumors of BWS, not all patients with the BWS spectrum will develop HBs. This observation has led to many hypotheses, including genotype-associated risk, tissue mosaicism, and tumor-specific second hits. To explore these hypotheses, we present the largest cohort of patients with BWS and HBs to date. Our cohort comprised 16 cases, and we broadened our sample size by searching the literature for all cases of BWS with HBs. From these isolated case studies, we amassed another 34 cases, bringing the total number to 50 cases of BWS-HB. We observed that paternal uniparental isodisomy (upd(11)pat) was the most common genotype, representing 38% of cases. The next most common genotype was IC2 LOM, representing 14% of cases. Five patients had clinical BWS without a molecular diagnosis. To investigate the potential mechanism of HBs in BWS, we analyzed normal liver and HB samples from eight cases and isolated tumor samples from another two cases. These samples underwent methylation testing, and 90% of our tumor samples underwent targeted cancer next-generation sequencing (NGS) panels. These matched samples provided novel insights into the oncogenesis of HBs in BWS. We found that 100% of the HBs that underwent NGS panel testing had variants in the CTNNB1 gene. We further identified three distinct groups of BWS-HB patients based on epigenotype. We also demonstrated epigenotype mosaicism, where 11p15 alterations can differ between the blood, HB, and normal liver. In light of this epigenotype mosaicism, tumor risk assessment based on blood profiling may not be accurate. Therefore, universal screening is recommended for all patients with BWS.

The treatment of hepatoblastoma: Its evolution and the current status as per the SIOPEL trials

Aim of the Review:

To describe the significant improvement in the diagnosis, treatment and outcome of children diagnosed with hepatoblastoma (HB) that has occurred in the past four decades. Recent findings are mainly focused on lessons learned from the experiences of the Childhood Liver Tumors Strategy Group (SIOPEL). Important milestones were the risk stratification of HB that allowed to tailor down therapy for standard-risk HB and intensify treatment for high-risk HB. The multi-institutional international cooperative SIOPEL trials are reviewed and current treatment guidelines are given. Intensified cooperation between the SIOPEL and the Children's Oncology Group (COG) and the national study groups from Germany (GPOH) and Japan (JPLT) led to the acceptance and use of one staging system (PRETEXT) and the formation of a single robust database containing data of 1605 HB patients. This will allow analysis with enough statistical power of treatment directing factors that will form one of the bases of the next-generation clinical trial that is currently designed by all four collaborating study groups.

Summary:

Successive SIOPEL trials and increasing international collaboration have improved survival rates of patients with HB through risk stratification, advances in chemotherapy and increased complete resection rates including liver transplantation as a surgical option.

Clinical, molecular- and cytogenetic analysis of a case of severe radio-sensitivity

In radiotherapy the normal tissue reaction is often a limiting factor for radiation treatment. Still there is no screening method, which predicts normal tissue reaction on radiotherapy, especially in comparison to tumor tissue, and therefore allows tailoring of the radiation dose to each patient. Here, we present a case of severe radiation-related side effects. We applied classical cytogenetic techniques (Giemsa-banding and staining of centromeric regions), the comet assay as well as multicolor fluorescence in situ hybridization on peripheral blood lymphocytes of this patient in order to determine the radio-sensitivity on the DNA level and to correlate these findings with the clinical outcome. Our investigations revealed abnormalities on chromosome 9, deficiencies in the DNA-repair capacity after radiation exposure and a high number of radiation induced chromosomal aberrations. A detected high amount of residual damage two or three hours after radiation exposure and repair as well as the high number of chromosomal aberrations (ChAs) suggests a correlation between repair capacity and radiation induced ChAs. We concluded that the detected abnormalities might serve as a genetic basis for the radio-sensitive phenotype of this patient. Taken together this report strengthens the idea that intensive DNA genomic analysis of individual patients can serve as the basis for more favourable treatment of cancer patients.

Risk of tumorigenesis in overgrowth syndromes: a comprehensive review

Overgrowth syndromes (OGS) comprise a heterogeneous group of disorders in which the main characteristic is that either weight, height, or head circumference is 2-3 standard deviations (SD) above the mean for sex and age. A striking feature of OGS is the risk of neoplasms. Here, the relative frequency of specific tumors in each OGS, topographic location, and age of appearance is determined by reviewing published cases. In some OGS (Perlman, Beckwith-Wiedemann, and Simpson-Golabi-Behmel syndromes and hemihyperplasia) more than 94% of tumors appeared in the abdomen usually before 10 years of age, mainly embryonal in type. In Perlman syndrome, only Wilms tumor has been recorded, whereas in Sotos syndrome, lympho-hematologic tumors are most frequent. Based on literature review, a specific schedule protocol for tumor screening is suggested for each OGS. A schedule with different intervals and specific tests is proposed for a more rational cost/benefit program for these disorders.

Where do we stand with hepatoblastoma? A review

Hepatoblastoma (HB) is the most common pediatric liver malignancy, comprising approximately 1% of all pediatric cancers. The disparate clinical staging systems and histologic classifications that were developed during the last decades, nevertheless, reflect the remaining difficulties and uncertainties in characterizing HB. Furthermore, the combination of surgery and (neo)adjuvant chemotherapy has improved patient outcomes dramatically. A poor prognosis is associated with large tumor size, multifocality, extrahepatic disease, and metastatic spread. The exact etiology of HB remains unknown, but the cytogenetic alterations, phenotypic features, and biologic aspects that accompany this neoplasm yield more and more insight into its pathogenesis. New cell-biologic and molecular-biologic insights may lead to the development of new treatment modalities, especially for patients with a bad prognosis. This review summarizes the different aspects of this intriguing tumor and discusses the current status of research and treatment for patients with HB.

A clinical overview of WT1 gene mutations

Mutations in the WT1 gene were anticipated to explain the genetic basis of the childhood kidney cancer, Wilms tumour (WT). Six years on, we review 100 reports of intragenic WT1 mutations and examine the accompanying clinical phenotypes. While only 5% of sporadic Wilms' tumours have intragenic WT1 mutations, > 90% of patients with the Denys-Drash syndrome (renal nephropathy, gonadal anomaly, predisposition to WT) carry constitutional intragenic WT1 mutations. WT1 mutations have also been reported in juvenile granulosa cell tumour, non-asbestos related mesothelioma, desmoplastic small round cell tumour and, most recently, acute myeloid leukemia.

Karyotypic analyses of hepatoblastoma. Report of two cases and review of the literature suggesting chromosomal loci responsible for the pathogenesis of this disease

Two cases of fetal hepatoblastoma with unique karyotypic changes are described. One was a 17-month-old boy with multiple unbalanced chromosomal translocations, resulting in four types of derivative chromosomes involving chromosomal loci at 1q21, 1q32, 2q23, 6q27, 7p22, and 21p12, partial tetrasomy of 1q, partial trisomy of 2q, and partial monosomy of 21p. The clonal karyotype of this tumor was 46,XY,der(2)t(1;2)(q32;q37), der(6)t(1;6)(q12;q27), der(7)t(2;7)(q23;p22), der(21)t(2;21) (q23;p12). In the other case, a 4-year-old girl, karyotypic analyses revealed trisomy 2 and 8, and the clonal karyotype of this case was 48,XX,+2,+8. Review of these cases together with previous reports suggested the significance of chromosomal changes including numerical abnormalities of 1q, 2(or 2q), 20, and 8 (or 8q), and breakage of 1q and 2q in the development of hepatoblastoma. The results presented herein underscore the significance of numerical abnormalities of chromosomal regions 1q and 2q and of chromosome 8 in the development of hepatoblastoma, in addition to abnormalities of 6q27, 7p22, and 21p12-13 as other chromosomal loci that may be responsible for the pathogenesis of this embryonal type of tumor.

Paternally inherited duplications of 11p15.5 and Beckwith-Wiedemann syndrome

We present a three generation family in which a father and son have a balanced chromosome translocation between the short arms of chromosomes 5 and 11 (karyotype 46,XY,t(5;11)(p15.3;p15.3)). Two family members have inherited the unbalanced products of this translocation and are trisomic for chromosome 11p15.3-->pter and monosomic for chromosome 5p15.3-->pter (karyotype 46,XY,der(5)t(5;11)(p15.3;p15.3)pat). Paternally derived duplications of 11p15.5 are associated with Beckwith-Wiedemann syndrome (BWS) and both family members trisomic for 11p15.5 had prenatal overgrowth (birth weights >97th centile), macroglossia, coarse facial features, and broad hands. We review the clinical features of BWS patients who have a paternally derived duplication of 11p15.5 and provide evidence for a distinct pattern of dysmorphic features in those with this chromosome duplication. Interestingly, our family is the fifth unrelated family to be reported with a balanced reciprocal translocation between the short arms of chromosomes 5 and 11. The apparently non-random nature of this particular chromosome translocation is suggestive of sequence homology between the two chromosome regions involved in the translocation.

Localization of a putative liver tumor suppressor locus to a 950-kb region of human 11p11.2-p12 using rat liver tumor microcell hybrid cell lines

We previously demonstrated that a locus (or loci) linked to the D11S436 marker, which is within the approximately 6-Mb cen-p12 region of human chromosome 11, suppresses the tumorigenic potential of some rat liver epithelial tumor microcell hybrid (MCH) cell lines. To more precisely map this putative liver tumor suppressor locus, we examined 25 loci from human chromosome 11 in suppressed MCH cell lines. Detailed analysis of these markers revealed a minimal area of overlap among the suppressed MCH cell lines corresponding to the chromosomal region bounded by (but not including) microsatellite markers D11S1319 and D11S1958E and containing microsatellite markers D11S436, D11S554, and D11S1344. Direct examination of the kang ai 1 (KA/1) prostatic adenocarcinoma metastasis suppressor gene (which is closely linked to D11S1344) produced evidence suggesting that this locus was not responsible for tumor suppression in this model system. In addition, our data strongly suggested that the putative liver tumor suppressor locus was distinct from other known 11p tumor suppressor loci, including the multiple exotoses 2 locus (at 11p11.2-p12), Wilms' tumor 1 locus (at 11p13), and Wilms' tumor 2 locus (at 11p15.5). The results of this study significantly narrowed the chromosomal location of the putative liver tumor suppressor locus to a region of human 11p11.2-p12 that is approximately 950 kb. This advance forms the basis for positional cloning of candidate genes from this region and, in addition, identified a number of chromosomal markers that will be useful for determining the involvement of this locus in the pathogenesis of human liver cancer.

Significance of extra copies of chromosome 20 and the long arm of chromosome 2 in hepatoblastoma

Cytogenetic analysis of both primary and metastatic hepatoblastoma revealed the following abnormal chromosomal complements respectively: 46,XX,der(2)t(2;2)(p25;q21),der(22)t(1;22)(q22;p13) [6]/47,XX,der(2)t(2;2)(p25;q21),+20,der(22)t(1;22)q22;p13)[4]/47,XX,der (2)t(2;2)(p25;q21), +20[1], and 48,XX,der(2)t(2;2)(p25;q21),+12,+17, -18,+20,der(22)t(1;22)(q22;p13)[9]/50,XX,der(2)t(2;2)(p25;q21), +8,+12,+17,+20[4]. Two abnormalities, the chromosome 2 derivative and trisomy 20, are recurrent in hepatoblastoma, but the derivative involving chromosomes 1 and 22 is a novel abnormality.

Nonimmune fetal hydrops and placentomegaly: diagnosis of familial Wiedemann-Beckwith syndrome with trisomy 11p15 using FISH

We have studied a family in which four members of the same generation were affected with Wiedemann-Beckwith syndrome (WBS). Trisomy 11p15 was demonstrated using molecular probes in interphase nuclei of formalin-fixed paraffin-embedded placenta from a stillborn fetus and in peripheral blood lymphocytes from two liveborn female relatives. Clinical examination showed nonimmune hydrops and placentomegaly in two siblings and multiple phenotypic abnormalities consistent with WBS in the two other relatives. Paternal karyotype of the stillborn infants demonstrated a reciprocal translocation (46,XY,t(10;11) (q26;p15)) explaining the origin of the extra 11p15 material. This study illustrates the advantages of FISH for interphase analysis of chromosome aberrations otherwise not detected even by conventional cytogenetic analysis and documents that nonimmune hydrops associated with placentomegaly may be the presenting features in familial WBS.

Favorable outcome in children with Beckwith-Wiedemann syndrome and intraabdominal malignant tumors

Children with Beckwith-Wiedemann syndrome (BWS) have an increased risk of developing Wilms' tumors, hepatoblastomas, and adrenal tumors. This study evaluates disease-free survival in children with BWS and intraabdominal tumors. Sixteen tumors occurred in 13 children with BWS (8 boys, 5 girls). Diagnoses included Wilms' tumor (10) (2 bilateral, 20%), hepatoblastoma (2), bladder rhabdomyosarcoma (1), and adrenal cortical tumor (1). In the 10 children with Wilms' tumor, the average age at diagnosis was 3.5 years (range, 7 months to 5 years). Nine of 10 had initial tumor resection, chemotherapy, and radiation therapy (when indicated). One child with bilateral disease had tumor biopsy, chemotherapy, and partial nephrectomy. Tumors were classified as stage I (5), stage II (2), stage IV (1) and stage V (2), all with favorable histology. Disease-free survival rate was 100% with median follow-up of 9 years (range, 4 to 22 years). One patient had a left adrenal tumor detected during screening sonography 11 years after Wilms' tumor resection. Two infants with advanced-stage hepatoblastoma responded to chemotherapy, allowing subsequent complete hepatic resection. Both tumors had unfavorable histology. Both completed postoperative chemotherapy and have no evidence of disease (NED) with normal alpha-fetoprotein levels at 21 and 12 months, respectively, after tumor detection. One patient with stage III (group 3) bladder rhabdomyosarcoma underwent partial cystectomy following chemoradiation and is alive (NED) after 20 months. Children with BWS should be screened at regular intervals (every 3 to 6 months) for renal, adrenal, and hepatic tumors. The exact duration of screening is not yet determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Occasional loss of constitutive heterozygosity at 11p15.5 and imprinting relaxation of the IGFII maternal allele in hepatoblastoma

The 11p15.5 chromosomal region contains one or more loci involved in congenital developmental abnormalities and in the genesis of embryonal tumors, such as Wilms' tumor, embryonal rhabdomyosarcoma, and hepatoblastoma. In these tumors, a loss of constitutive heterozygosity, selectively involving a specific parental allele, suggests both the presence of onco-suppressor genes and a phenomenon of genomic imprinting. We present evidence that both genetic events could be occasionally involved in hepatoblastoma. In fact, loss of heterozygosity at 11p15.5 could be documented in 3 of 13 patients with hepatoblastoma, and in 2 cases the paternal origin of the residual allele in the tumor was assessed. Moreover, imprinting of the paternal IGFII allele and the maternal H19 allele was confirmed in normal tissues of 5 informative patients. Finally, imprinting relaxation of IGFII was detected in the tumor tissue of 1 patient.

Sex dependent transmission of Beckwith-Wiedemann syndrome associated with a reciprocal translocation t(9;11)(p11.2;p15.5)

Beckwith-Wiedemann syndrome (BWS), a disorder associated with neonatal hypoglycaemia, increased growth potential, and predisposition to Wilms's tumour (WT) and other malignancies, has been mapped to 11p15. The association with 11p15 duplications of paternal origin, of balanced translocations and inversions with breakpoints within 11p15.4-p15.5 of maternal origin, and the demonstration of uniparental paternal 11p15 isodisomy in some sporadic cases point towards the involvement of genomic imprinting. In agreement with this, we show the paternal origin of a de novo 9;11 translocation in a phenotypically normal mother, whose carrier daughter developed BWS. This supports the fact that BWS associated with balanced chromosome mutations is transmitted in the same sex dependent pattern as non-cytogenetic forms of familial BWS.

Evidence for paternal imprinting in familial Beckwith-Wiedemann syndrome

A previously unreported family in which seven members in two generations have Beckwith-Wiedemann syndrome (BWS) is documented. Paternal imprinting of the gene responsible for BWS is involved as the mechanism responsible for the aberrant inheritance pattern in this kindred. A review of published reports showed 27 previously published pedigrees with two or more affected subjects with BWS. Paternal imprinting would explain the non-mendelian inheritance of BWS in all but four kindreds. The latter families are examined in more detail and in only one example is the evidence against imprinting totally unexplained.

Trisomy 2 and 20 in two hepatoblastomas

Cytogenetic analysis of two pediatric hepatoblastomas is presented, comparing results in primary tumor samples, nude mouse xenographs, and lung metastases in one case. Both tumors had trisomy 2 and 20 in the primary tumors, along with other structural abnormalities. In subsequent passages/metastases, both tumors showed structural changes in one chromosome 2, resulting in partial trisomy 2q, along with structural changes of other chromosomes. Partial trisomy 1q was also common to both tumors in late stages. Results are compared to those of embryonal rhabdomyosarcoma, where trisomy 2 has also been noted.

Congenital gastric teratoma in Wiedemann-Beckwith syndrome

Wiedemann-Beckwith syndrome (WBS) may be associated with abdominal tumors, including Wilms tumor, adrenocortical carcinoma, hepatoblastoma, gonadoblastoma, rhabdomyosarcoma, and neuroblastoma. We report on a newborn infant with WBS and a congenital teratoma of the stomach. This is the sole report of any teratoma being associated with WBS and also the first report of a tumor present at birth and visible prenatally in WBS. At birth this infant boy had the diagnostic findings of WBS with macroglossia, ear lobule creases and pits, nevus flammeus, and omphalocele, and an abdominal mass. Abnormalities were detected prenatally when ultrasound examination showed placental overgrowth, polyhydramnios, omphalocele, and posterior abdominal calcifications. Resection of the mass and partial gastrectomy were performed at age 10 days; histologic study showed an immature grade-II teratoma containing a mixture of mature and immature tissues from all germ layers. Results of cytogenetic studies of blood and teratoma were normal (46,XY). This congenital gastric teratoma in a newborn boy with classical WBS may represent either a tumor or an included twin. We discuss its implications for the association of WBS with neoplasia and monozygotic (MZ) twinning, review various neoplasias associated with WBS, and consider pathogenetic mechanisms.

Neuroblastoma in a child with Wiedemann-Beckwith syndrome

We report on a patient with Wiedemann-Beckwith syndrome (WBS) who developed abdominal neuroblastoma. Although WBS patients are known to have a higher incidence of embryonal tumors, this is only the 4th known case of neuroblastoma associated with this syndrome. Chromosomes on peripheral lymphocytes and tumor cells were normal. Children with WBS should be screened for a variety of embryonal neoplasms, not only Wilms tumor.

Epidemiological and familial aspects of hepatoblastoma

Data on the 20 cases of hepatoblastoma registered with the Manchester Children's Tumour Registry between 1954 and 1988 are presented. The cases represent about 0.6% of childhood malignancies and show a male:female ratio of 2.3:1. Age at presentation was almost always under 2 1/2 years. Cancer rates in close relatives were not significantly different from those expected. One family was confirmed as having Gardner syndrome, but the presence of other syndromes e.g., Beckwith-Wiedemann, could not be reliably detected in this retrospective series. The need to take an extensive pedigree and for clinical examination of other family members at the time of the child's diagnosis is emphasized.

Loss of alleles on the short arm of chromosome 11 in a hepatoblastoma from a child with Beckwith-Wiedemann syndrome

The Beckwith-Wiedemann syndrome (BWS) is characterised by multiple congenital abnormalities, including exomphalos, macroglossia, and gigantism. It is also associated with an elevated risk of embryonal neoplasia and occasionally with constitutional anomalies of chromosome band 11p15. A common pathogenetic mechanism for the development of several embryonal tumours has been proposed involving the loss of somatic heterozygosity for a locus on the short arm of chromosome 11. In support of this hypothesis, we have recently reported generation of homozygosity for the c-Ha-ras-1 protooncogene in an adrenal adenoma from an adult BWS patient. In this study we report the generation of homozygosity for a region on the short arm of chromosome 11 defined by the calcitonin (11p13-15) and insulin (11p15-15.1) genes in a hepatoblastoma from a child with BWS.

Generation of homozygosity at the c-Ha-ras-1 locus on chromosome 11p in an adrenal adenoma from an adult with Wiedemann-Beckwith syndrome

Generation of homozygosity for the human c-Ha-ras-1 locus on the short arm of chromosome #11 (11p) has been demonstrated for an adrenal adenoma from an adult with Wiedemann-Beckwith syndrome (WBS). This is the first demonstration of loss of somatic heterozygosity for a locus on 11p in an adrenal neoplasm and is the first instance where a tumor of any type, from a patient with WBS, shows loss of heterozygosity in this region of the genome. Generation of homozygosity in an adenoma, rather than a carcinoma, demonstrates that this mechanism is an early event in tumorigenesis rather than a late event associated with tumor progression.

Molecular approaches to developmental genetics and pathology

New insights into gene structure and expression and the observation that homeobox-containing genes, the t-complex, and oncogenes are expressed also in humans contribute to the understanding of normal and pathobiological mechanisms of embryonal and fetal development.