Hormonal treatment in pregnancy: a possible risk factor for neuroblastoma

Maternal use of fertility drugs and risk of cancer in children--a nationwide population-based cohort study in Denmark

Large population-based studies are needed to examine the effect of maternal use of fertility drugs on the risk of cancer in children, while taking into account the effect of the underlying infertility. A cohort of 123,322 children born in Denmark between 1964 and 2006 to 68,255 women who had been evaluated for infertility was established. We used a case-cohort design and calculated hazard ratios (HRs) for cancer in childhood (0-19 years) and in young adulthood (20-29 years) associated with maternal use of six groups of fertility drugs (clomiphene, gonadotropins [i.e., human menopausal gonadotropins and follicle-stimulating hormone], gonadotropin-releasing hormone analogs, human chorionic gonadotropins, progesterone and other fertility drugs). We found no statistically significant association between maternal use of fertility drugs and risk for overall cancer in childhood or young adulthood. However, with regard to specific cancers in childhood, our results showed that maternal use of progesterone before childbirth markedly increased the risks of their offspring for acute lymphocytic leukemia (any use: HR, 4.95; 95% CI, 1.69-14.54; ≥ three cycles of use: HR, 9.96; 95% CI, 2.63-37.77) and for sympathetic nervous system tumors (any use: HR, 5.79; 95% CI, 1.23-27.24; ≥ three cycles of use: HR, 8.51; 95% CI, 1.72-42.19). These findings show that maternal use of progesterone may increase the risk for specific cancers in the offspring. Additional large epidemiological studies are urgently needed to confirm our finding.

Atypical teratoid/rhabdoid tumor in an infant conceived by in vitro fertilization

BACKGROUND

Atypical teratoid/rhabdoid tumor (ATsRT) is a rare tumor and extremely aggressive embryonal neoplasm of the central nervous system. Brain tumors in infant are suggestive of some oncogenic prenatal factors.

CASE PRESENTATION

We report on a case of ATRT in a 4-month-old infant conceived by in vitro fertilization (IVF). Some previous reports have raised a question about the possible relation between IVF and childhood cancer, particularly embryonal tumors.

CONCLUSION

Report of such cases may provide some evidence to identify if there is a real association between congenital tumors and IVF.

8q deletion in MYCN-amplified neuroblastoma of a child born from assisted reproductive technology

The occurrence of pediatric cancer in children born from assisted reproductive technologies has been sporadically reported. Chromosomal characterization of the neoplasic disease in this setting is poorly described. In the present study, neuroblastoma cells from a 13-month-old infant boy born after intracytoplasmatic sperm injection were characterized by combining conventional cytogenetics, fluorescence in situ hybridization (FISH), comparative genomic hybridization, and quantitative polymerase chain reaction methods. Cytogenetic analysis of neuroblastoma (NB) metaphase spreads at the time of diagnosis revealed numerous centromere-free extrachromosomal double minutes, suggesting high MYCN amplification. Comparative genomic hybridization analysis demonstrated the amplification of 2q24 approximately pter, with additional gain of the long arm of chromosome 17. Chromosome losses involved 8q, 9q, and 11q. No deletion of 1p was found. MYCN amplification was confirmed by quantitative polymerase chain reaction and fluorescence in situ hybridization analysis. This report describes several chromosomal abnormalities that were present in NB of a child born after intracytoplasmatic sperm injection. Besides some well described and prognostic genetic findings in NB as MYCN amplification, gain on 17q and losses on 9q and 11q23, we report an unusual deletion involving 8q region in this disease. Whether this genetic abnormality may be associated to assisted reproductive technologies deserves further investigation.

Growth and development of children born after in vitro fertilization

OBJECTIVE

To evaluate growth and development of children born after IVF treatment.

DESIGN

Literature review.

CONCLUSION(S)

At present there is substantial evidence that children born after IVF are at increased risk for adverse perinatal outcome, congenital malformations, and rare epigenetic defects. It is still unclear whether observed health problems originate from the IVF procedure itself or the underlying subfertility problems of the parents. Current follow-up studies regarding postnatal growth and morbidity rates are scarce with conflicting results and other areas of long-term research in children born after IVF are still in its infancy. The importance of the worldwide continuing monitoring of children born after IVF to investigate potential long-term consequences including the development of cardiovascular diseases is therefore highlighted.

Factores de riesgo para el neuroblastoma

INTRODUCTION

NB is the most frequent pediatric cancer arising in the sympathetic nervous system and represents a serious healthcare challenge because: 1) it is the most frequent neoplasm in the first decades of life; 2) it biological behavior is unpredictable (spontaneous regression, maturation to ganglioneuroma, and localized and metastasized variants); and 3) little is known about most of the risk factors involved in its etiopathogenesis. The objective of this study was to disseminate knowledge of constitutional and environmental (physical, chemical, biological and social) risk factors linked to the development of neuroblastoma (NB), with various levels of scientific evidence. To seek collaboration among pediatricians in the research project "Environment and Pediatric Cancer".

MATERIAL AND METHODS

We performed a systematic review of the literature published in the previous 25 years on risk factors for NB diagnosed in the first two decades of life, using Medline, the Science Citation Index and Embase. Search profiles were: "neuroblastoma/childhood sympathetic nervous system neoplasms and risk factors/etiology/epidemiology". The most interesting articles and the most relevant references contained therein were selected.

RESULTS

With greater or lesser scientific evidence, the following risk factors increase the risk of developing NB: genetic factors; geographic factors; ethnic factors; socioeconomic factors; infectious factors; physical factors; parental occupational exposure; gestational factors; and perinatal and maternal factors. Preventive factors associated with a lower risk of developing NB are breastfeeding and intake of vitamin supplements during pregnancy.

CONCLUSIONS

The main barriers to the identification of evidence-based risk factors involved in the development of NB are its complex biology and clinical course, its relative rarity and the difficulty of performing epidemiological studies. Research on constitutional and environmental factors involved in its etiopathogenesis should be stimulated. The best preventive strategy is to recommend breastfeeding for more than 6 months.

Childhood tumor risk after treatment with ovulation-stimulating drugs

OBJECTIVE

To assess childhood cancer risk among children conceived following the use of ovulation-stimulating drugs.

DESIGN

Record linkage study.

SETTING

Infertility patients and their offspring as identified through medical records.

PATIENT(S)

Cohort of 30,364 Danish women evaluated for infertility beginning in the early 1960s.

MAIN OUTCOME MEASURE(S)

Standardized incidence ratios (SIRs) compared cancer incidence in the children to the Danish population. Case-cohort techniques calculated rate ratios (RRs) according to prior maternal drug exposures.

RESULT(S)

A total of 51 cancers were identified among the study children, resulting in an SIR of 1.14 (95% confidence interval [CI] 0.8-1.5). Usage of any fertility drug was associated with an RR of 0.82 (95% CI 0.4-1.6) and clomiphene citrate with an RR of 0.77 (95% CI 0.4-1.6). Tumors occurring early in life and nonhematopoietic malignancies (including neuroblastomas) were not associated with drug usage. Nonsignificant elevations in the risk of cancers occurring later in life, especially childhood hematopoietic malignancies (RR for use of any ovulation-stimulating drugs of 2.30, 95% CI 0.8-6.6), may have been related to underlying reasons for medication usage.

CONCLUSION(S)

Although the findings of this study are reassuring, additional adequately powered studies should continue monitoring the effects of ovulation-stimulating drugs on specific tumors, including hematopoietic malignancies.

Perinatal factors and risk of neuroblastoma

Neuroblastoma is a malignancy commonly diagnosed during infancy or early childhood, raising speculation about the role of perinatal factors and risk of disease. Using a case-control design, cases included 155 infants and children aged 0-5 years with histologically confirmed neuroblastoma diagnosed and reported to the New York State Cancer Registry between 1976 and 1987. Controls were randomly selected from the State's Livebirth Registry and were frequency matched to cases on year of birth (n = 310). Medical records of cases were used to verify histology and stage of disease. Data on perinatal factors were ascertained from birth certificates and standardised telephone interviews with mothers. Unconditional logistic regression was used to estimate (un)adjusted odds ratios (OR) and 95% confidence intervals (CI). Both preterm (< 37 weeks) and post-term (> 42 weeks) birth were associated with a reduction in risk (OR = 0.4 [CI = 0.1, 0.9] and OR = 0.3 [CI = 0.1, 0.7] respectively) after controlling for confounders in unconditional logistic regression analysis. Elevated risk factors included: smoking during pregnancy (OR = 1.6; CI = 0.9, 2.8), contracted pelvis (OR = 2.3; CI = 0.6, 9.8), birth injury (OR = 2.9; CI = 0.3, 24.9) and 1-min Apgar Score < or =3 (OR = 6.0; CI = 0.9, 38.6); all confidence intervals included one. These data suggest that extremes in gestation may be associated with a reduced risk, although aetiological mechanisms remain unknown.

The risk for cancer among children of women who underwent in vitro fertilization

BACKGROUND

The possible association between ovarian carcinoma and ovulation-inducing drugs has led to renewed interest in the potential carcinogenic risks of these drugs. In vitro fertilization (IVF) has been linked to multiple pregnancies and possibly congenital malformations. However, to the authors' knowledge the association between IVF and pediatric cancer has been described only in sporadic case reports. The aim of this study was to assess the incidence rate of pediatric cancer among a cohort of children born after IVF.

METHODS

A historic prospective study based on a cohort of 332 children from 1254 women who underwent IVF treatment between 1981-1994 was performed. Medical files were reviewed and names were linked to the National Population and Cancer Registries. Pediatric cancer incidence rates were compared with the expected age-adjusted rates of the general population during the respective time period.

RESULTS

No cancer cases were observed among the study cohort with respect to 1.7 cases that were expected.

CONCLUSIONS

Because the small cohort analysis in the current study lacked the necessary power to reach definite conclusions, larger prospective studies are needed to assess the potential carcinogenic effect on children born after ovulation induction and IVF.

Effects and metabolism of steroid hormones in human neuroblastoma cells

The development of the central nervous system is influenced by sex steroids and by their metabolites. However, little information on the possible effects of steroid hormones on neuroblastoma cells is available. Human neuroblastoma cell lines have been used as a model of human neuroblasts in vitro to study the metabolism of steroid hormones; in addition, the effects of steroids and steroid antagonists on neuroblastoma cell growth have also been investigated. The results obtained show that SH-SY5Y human neuroblastoma cells may actively metabolize testosterone and progesterone to their respective 5 alpha-reduced metabolites and that differentiation of neuroblastoma cells is paralleled by a significant increase in expression of the type-1 5 alpha-reductase and of the formation of steroid metabolites. All these data are suggestive of a potential role of steroid 5 alpha-reduced metabolites in the biology of neuroblastoma cells. Studies performed to analyze the role of steroid hormones on neuroblastoma cell proliferation show that progesterone at low doses may induce minor stimulation, and at higher doses, a toxic effect on the neuroblastoma cell line SK-N-SH is seen. Moreover, the antiprogestin 17 beta-hydroxy-11 beta-(4-dimethylamino-phenyl-1)-17-(prop-1-ynyl)estra-4,9-dien+ ++-3-one (RU486) decreases the proliferation of these cells in a dose-dependent manner. The effect of RU486 is not antagonized by either progesterone or dexamethasone, a result that seems to exclude the action of RU486 via classic intracellular steroid hormone receptors.

Pediatric cancer: environmental and genetic aspects

One in 600 children 0-16 years of age develop cancer, and 60% to 70% of them are cured. Projection of the data indicates that by the turn of the century, 1 of every 900 individuals between the ages of 16 and 44 years will be a cancer survivor. In the adult population, carcinogens and irradiation play a major role in oncogenesis. In the pediatric population other factors are probably dominant. Children of low socioeconomic groups, with nutritional deficiencies, are more exposed to viral infections at a very early age and have a greater chance of developing tumors such as Burkitt lymphoma or mixed cellularity Hodgkin disease. Other factors such as hormone-assisted conception or in vitro fertilization may have carcinogenic potential, although this has yet to be determined. Maternal diet during pregnancy, especially low folic acid consumption periconception, may have bearing on the fetus's risk of developing malignancy. The hazards of exposure to electric and magnetic fields from high-voltage transmission lines, home electric appliances, video display terminals, or residence near nuclear plants, although very doubtful, are included in the list of cancer promoters in children. Activated oncogenes, mutated suppressor genes, mismatch repair genes, nucleotide excision genes, and loss of imprinting genes are beginning to evolve as important factors in carcinogenesis. The more in-depth information on genetic and environmental factors should provide new data on the evolution of pediatric tumors and possibly on their prevention.

Two embryonal cancers after in vitro fertilization

BACKGROUND

In vitro fertilization is not considered to be associated with an increased rate of pediatric malignancies, and only three have been reported in the literature. Two additional rare pediatric tumors in children conceived through this technique are reported.

METHODS

Two children 12 and 18 months of age, developed hepatoblastoma and clear cell sarcoma of the kidney, respectively. They were both products of uneventful pregnancies induced by in vitro fertilization. No other environmental, prenatal, or family factor was found.

RESULTS

The first child died after a failed remission induction with cisplatin, doxorubicin, and vincristine, whereas the second child is alive with no evidence of disease 18 months after diagnosis and treatment according to NWTS protocol.

CONCLUSIONS

A possible association between in vitro fertilization and pediatric malignancies is suggested.