Congenital anomalies and genetic disorders in families of children with central nervous system tumours

A lasting symbiosis: how the Hawaiian bobtail squid finds and keeps its bioluminescent bacterial partner

For more than 30 years, the association between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium Vibrio fischeri has been studied as a model system for understanding the colonization of animal epithelia by symbiotic bacteria. The squid-vibrio light-organ system provides the exquisite resolution only possible with the study of a binary partnership. The impact of this relationship on the partners' biology has been broadly characterized, including their ecology and evolutionary biology as well as the underlying molecular mechanisms of symbiotic dynamics. Much has been learned about the factors that foster initial light-organ colonization, and more recently about the maturation and long-term maintenance of the association. This Review synthesizes the results of recent research on the light-organ association and also describes the development of new horizons for E. scolopes as a model organism that promises to inform biology and biomedicine about the basic nature of host-microorganism interactions.

Congenital neurodevelopmental anomalies in pediatric and young adult cancer

Congenital anomalies that are diagnosed in at least 120,000 US infants every year are the leading cause of infant death and contribute to disability and pediatric hospitalizations. Several large-scale epidemiologic studies have provided substantial evidence of an association between congenital anomalies and cancer risk in children, suggesting potential underlying cancer-predisposing conditions and the involvement of developmental genetic pathways. Electronic medical records from 1,107 pediatric, adolescent, and young adult oncology patients were reviewed. The observed number (O) of congenital anomalies among children with a specific pediatric cancer subtype was compared to the expected number (E) of anomalies based on the frequency of congenital anomalies in the entire study population. The O/E ratios were tested for significance using Fisher's exact test. The Kaplan-Meier method was used to compare overall and neurological malignancy survival rates following tumor diagnosis. Thirteen percent of patients had a congenital anomaly diagnosis prior to their cancer diagnosis. When stratified by congenital anomaly subtype, there was an excess of neurological anomalies among children with central nervous system tumors (O/E = 1.56, 95%CI 1.13-2.09). Male pediatric cancer patients were more likely than females to have a congenital anomaly, particularly those <5 years of age (O/E 1.35, 95%CI 0.97-1.82). Our study provides additional insight into the association between specific congenital anomaly types and pediatric cancer development. Moreover, it may help to inform the development of new screening policies and support hypothesis-driven research investigating mechanisms underlying tumor predisposition in children with congenital anomalies.

Family history of cancer among children with brain tumors: a critical review

The occurrence of brain tumors in children has been anecdotally associated with an increased cancer incidence among relatives. This study rigorously reviewed the epidemiologic literature regarding family history of cancer in children with brain tumors. Six case-control and 10 cohort studies remained after applying stringent inclusion criteria. Most studies found no significant increase in cancer risk among relatives of childhood brain tumor patients. Those associations that were detected were often of borderline significance or demonstrated wide confidence intervals. There is limited evidence that a family history of cancer is more common among families of childhood brain tumor patients.

Clinical manifestations of genetic instability overlap one another

Cancer syndromes are characteristic associations of specific malignancies with various congenital anomalies. In addition to such diseases, an increased prevalence in general of chromosomal instability, malformations, immunodeficiencies, altered growth and development, and reproductive loss has been observed in both childhood leukemias and solid tumors. The overlap among these congenital disorders suggests their common prenatal, possibly genetic origin and thus the existence of a nonspecific genetic instability leading to various clinical manifestations of disturbances in cell division. Seeking for related features in family members of a patient with malignancy may be of clinical value in detecting predisposition to cancer.

Cancer in siblings of children with cancer in the Nordic countries: a population-based cohort study

BACKGROUND

In some rare inherited disorders such as Li-Fraumeni syndrome, relatives of children with cancer are at increased risk of cancer. We aimed to assess relations between childhood cancer and sibling risk, and evaluate the influence of recessive conditions in cancer causation.

METHODS

We did a population-based cohort study in the Nordic countries of 42277 siblings of 25605 children with cancer. Children with cancer were identified from records in the five Nordic cancer registries, and their siblings from nationwide population registries. Cancers in siblings were documented through record linkage with cancer registries and compared with national incidence rates. We also assessed cancer incidence in parents to identify familial cancer syndromes.

FINDINGS

284.2 cancers were expected in siblings, whereas 353 were diagnosed (standardised incidence ratio 1.24 95% CI 1.12-1.38). Risk ratios for siblings were highest in the first decade of life (2.59, 1.89-3.46). We excluded 56 families with genetic syndromes linked to cancer, which reduced this ratio from 1.7 to 1.0 (0.7-1.3) for siblings younger than 20 years, and from 1.3 to 1.0 (0.8-1.3) for those aged 20-29 years. We found no new patterns of familial cancer that indicated inherited susceptibility, or evidence that recessive conditions might contribute to cancers not explained by syndromes. 40% of cancers in siblings that occurred before age 20 years could be attributed to known genetic factors, whereas 60% remained unexplained.

INTERPRETATION

Apart from rare cancer syndromes, paediatric cancer is not an indicator of increased cancer risk in siblings.

Molecular insight into medulloblastoma and central nervous system primitive neuroectodermal tumor biology from hereditary syndromes: a review

Through the study of uncommon familial syndromes, physicians and scientists have been able to illuminate the underlying mechanisms of some of the more common sporadic diseases; this is illustrated best by studies of familial retinoblastoma. A number of rare familial syndromes have been described in which affected individuals are at increased risk of developing medulloblastoma and/or supratentorial primitive neuroectodermal tumors. The descriptions of many of these syndromes are based on patients observed by clinicians in their clinical practice. Determination of the underlying genetic defects in these patients with uncommon syndromes has led to identification of a number of genes subsequently found to be mutated in sporadic medulloblastomas (tumor suppressor genes). Associated genes in the same signaling pathways have also been found to be abnormal in sporadic medulloblastoma. Identification of patients with these rare syndromes is important, as they are often at increased risk for additional neoplasms, as are family members and future children. We review the published literature describing hereditary syndromes that have been associated with an increased incidence of medulloblastoma and/or central nervous system primitive neuroectodermal tumor. Review of the underlying molecular abnormalities in comparison to changes found in sporadic neoplasms suggests pathways important for tumorigenesis.

Neurologic and other disorders in relatives of pediatric patients with CNS tumors

Abnormalities of embryogenesis and nervous system development may cause or contribute to the development of childhood brain tumors. To identify genetic or environmental factors that may be associated with etiologies of childhood central nervous system tumors, we examined family histories of 165 children with such tumors for the presence of neurologic disorders, including neural tube defects, mental retardation, seizures, and central nervous system tumors, as well as other cancers and birth defects. Only 1 patient, with the neurofibromatosis-Noonan syndrome, was confirmed to have an underlying syndromic diagnosis associated with central nervous system tumorigenesis. Families of 2 probands with posterior fossa primitive neuroectodermal tumors reported relatives with olivopontocerebellar atrophy. Although increased incidences of study disorders were not identified in this population, it is possible that within individual families one or more of these disorders is related to childhood central nervous system tumorigenesis.