Parental Occupation and Risk of Childhood Retinoblastoma in Denmark

OBJECTIVE

Retinoblastoma is the most common primary intraocular tumor affecting children. We examine the role of parental occupational exposures and risk of retinoblastoma among offspring.

METHODS

Our population-based case-control study linked data from four nationwide Danish registries and included all cases of retinoblastoma diagnosed in Danish children (<5 y, n = 144) between 1975 and 2014. We focused on two biologically relevant time periods: 90 days preconception to conception for fathers; conception to birth for mothers. Parents were grouped into major industry headings created from Danish industry codes.

RESULTS

We observed increased risk of all retinoblastoma for children of fathers in the food and drink industry and iron and metal industry. Bilateral disease was associated with paternal work in manufacturing and land transportation.

CONCLUSION

Our results suggest that some occupational exposures may increase the risk of childhood sporadic retinoblastoma.

Patterns of Cause-Specific Mortality Among 2053 Survivors of Retinoblastoma, 1914-2016

BACKGROUND

Previous studies of hereditary retinoblastoma survivors have reported elevated mortality, particularly for sarcomas, compared with the general population. However, cause-specific mortality patterns for long-term hereditary and nonhereditary retinoblastoma survivors are poorly understood.

METHODS

Among 2053 retinoblastoma patients diagnosed during 1914-2006 at two major US treatment centers and followed to 2016, we estimated cumulative mortality, standardized mortality ratios (SMRs), and absolute excess risks (AERs) compared with the US general population.

RESULTS

Most deaths occurred in 1129 hereditary retinoblastoma patients (n = 518 deaths, cumulative mortality 70 years after retinoblastoma = 75.8%, 95% CI = 69.0% to 82.6%; SMR = 8.5, 95% CI = 7.7 to 9.2). Of these, 267 were due to subsequent cancers (SMR = 27.4, 95% CI = 24.2 to 30.9; AER = 72.3 deaths/10 000 person-years), for which SMRs were highest 15-29 years after diagnosis (n = 69, SMR = 89.9, 95% CI = 70.0 to 113.8) but remained statistically significantly elevated at 60 and more years (n = 14, SMR = 6.7, 95% CI = 3.6 to 11.2), whereas AERs increased with time (AER<15years = 38.0; AER60+years = 327.5). Increased risk of death due to cancers of pancreas, large intestines, and kidney were noted for the first time. Overall risk of subsequent cancers was greater for those treated with radiotherapy and chemotherapy compared to radiotherapy alone, although patterns varied by organ site. For 924 patients with nonhereditary retinoblastoma, we noted a modestly increased risk of death for subsequent cancers (n = 27, SMR = 1.8, 95% CI = 1.2 to 2.6) possibly due to treatment or misclassification of hereditary status. Risks of noncancer causes of death were not elevated for hereditary or nonhereditary patients.

CONCLUSION

Hereditary retinoblastoma survivors died mainly from an excess risk of subsequent cancers up to six decades later, highlighting the need to develop long-term clinical management guidelines for hereditary retinoblastoma survivors treated in the past.

Retinoblastoma in Patients with 13q deletion syndrome - case series

Deletion of the long arm of chromosome 13 (13q deletion syndrome) is very rare chromosomal aberration which causes mental retardation and multiple congenital malformations. Furthermore, it is associated with the increased risk of retinoblastoma. The aim of the paper was to present two cases of retinoblastomna in children with 13q deletion syndrome, discussing the diagnostic and therapeutic management, clinical manifestation and the importance of genetic testing which helps to determine the type of retinoblastoma and may also contribute to the diagnosis of other congenital abnormalities associated with intraocular tumors.

Sporadic Retinoblastoma and Parental Smoking and Alcohol Consumption before and after Conception: A Report from the Children's Oncology Group

Background

Retinoblastoma is the most frequent tumor of the eye in children and very little is known about the etiology of non-familial (sporadic) retinoblastoma. In this study we examined whether parental tobacco smoking or alcohol consumption (pre- or post-conception) contribute to the two phenotypes (bilateral or unilateral) of sporadic retinoblastoma.

Methods

Two large multicenter case-control studies identified 488 cases through eye referral centers in the United States and Canada or through the Children’s Oncology Group. Controls (n = 424) were selected from among friends and relatives of cases and matched by age. Risk factor information was obtained via telephone interview. We employed multivariable logistic regression to estimate the effects of parental tobacco smoking and alcohol consumption on retinoblastoma.

Findings

Maternal smoking before and during pregnancy contributed to unilateral retinoblastoma risk in the child: year before pregnancy conditional Odds Ratio (OR), 8.9; 95% confidence interval (CI) 1.5–51, and unconditional OR, 2.4; 95% CI, 1.3–4.7; month before or during pregnancy, conditional OR, 3.3; 95% CI, 0.5–20.8, and unconditional OR, 2.8; 95% CI, 1.1–7.0. No association was found for maternal or paternal alcohol consumption.

Conclusion

The results of this study indicate that maternal active smoking during pregnancy may be a risk factor for sporadic retinoblastoma. Our study supports a role for tobacco exposures in embryonal tumors.

Spatiotemporal Patterns of Tumor Occurrence in Children with Intraocular Retinoblastoma

PURPOSE

To accurately map the retinal area covered by tumor in a prospectively enrolled cohort of children diagnosed with retinoblastoma.

METHODS

Orbital MRI in 106 consecutive retinoblastoma patients (44 bilateral) was analyzed. For MRI-visible tumors, the polar angle and angle of eccentricity of points defining tumor perimeter on the retina were determined by triangulation from images in three orthogonal planes. The centroid of the mapped area was calculated to approximate tumor origin, and the location and cumulative tumor burden were analyzed in relation to mutation type (germline vs. somatic), tumor area, and patient age at diagnosis. Location of small tumors undetected by MRI was approximated with fundoscopic images.

RESULTS

Mapping was successful for 129 tumors in 91 eyes from 67 patients (39 bilateral, 43 germline mutation). Cumulative tumor burden was highest within the macula and posterior pole and was asymmetrically higher within the inferonasal periphery. Tumor incidence was lowest in the superotemporal periphery. Tumor location varied with age at diagnosis in a complex pattern. Tumor location was concentrated in the macula and superonasal periphery in patients <5.6 months, in the inferotemporal quadrant of the posterior pole in patients 5.6-8.8 months, in the inferonasal quadrant in patients 8.8-13.2 months, and in the nasal and superotemporal periphery in patients >13.2 months. The distribution of MRI-invisible tumors was consistent with the asymmetry of mapped tumors.

CONCLUSIONS

MRI-based mapping revealed a previously unrecognized pattern of retinoblastoma localization that evolves with age at diagnosis. The structured spatiotemporal distribution of tumors may provide valuable clues about cellular or molecular events associated with tumorigenesis in the developing retina.

Prenatal exposure to traffic-related air pollution and risk of early childhood cancers

Exposure to air pollution during pregnancy has been linked to the risk of childhood cancer, but the evidence remains inconclusive. In the present study, we used land use regression modeling to estimate prenatal exposures to traffic exhaust and evaluate the associations with cancer risk in very young children. Participants in the Air Pollution and Childhood Cancers Study who were 5 years of age or younger and diagnosed with cancer between 1988 and 2008 were had their records linked to California birth certificates, and controls were selected from birth certificates. Land use regression-based estimates of exposures to nitric oxide, nitrogen dioxide, and nitrogen oxides were assigned based on birthplace residence and temporally adjusted using routine monitoring station data to evaluate air pollution exposures during specific pregnancy periods. Logistic regression models were adjusted for maternal age, race/ethnicity, educational level, parity, insurance type, and Census-based socioeconomic status, as well as child's sex and birth year. The odds of acute lymphoblastic leukemia increased by 9%, 23%, and 8% for each 25-ppb increase in average nitric oxide, nitrogen dioxide, and nitrogen oxide levels, respectively, over the entire pregnancy. Second- and third-trimester exposures increased the odds of bilateral retinoblastoma. No associations were found for annual average exposures without temporal components or for any other cancer type. These results lend support to a link between prenatal exposure to traffic exhaust and the risk of acute lymphoblastic leukemia and bilateral retinoblastoma.

Risk of retinoblastoma is associated with a maternal polymorphism in dihydrofolatereductase (DHFR) and prenatal folic acid intake

BACKGROUND

The incidence of unilateral retinoblastoma varies globally, suggesting possible environmental contributors to disease incidence. Maternal intake of naturally occurring folate from vegetables during pregnancy is associated inversely with the risk of retinoblastoma in offspring.

METHODS

The authors used a case-control study design to examine the association between retinoblastoma risk and maternal variations in the folate-metabolizing genes methylenetetrahydrofolate reductase (MTHFR) (a cytosine-to-thymine substitution at nucleotide 677 [MTHFR677C→T]; reference single nucleotide polymorphism rs1801133) and dihydrofolate reductase (DHFR) (a 19-base-pair deletion of intron 1a [DHFR19bpdel]; rs70991108). In central Mexico, 103 mothers of children with newly diagnosed unilateral retinoblastoma were enrolled in an institutional review board-approved study along with a control group of 97 mothers who had healthy children. Mothers were interviewed regarding perinatal characteristics, including use of prenatal vitamin supplements, and gave peripheral blood samples, which were used for polymerase chain reaction-based genotyping of rs1801133 and rs70991108.

RESULTS

The risk of having a child with unilateral retinoblastoma was associated with maternal homozygosity for DHFR19bpdel (odds ratio, 3.78; 95% confidence interval, 1.89-7.55; P = .0002), even after controlling for the child's DHFR19bpdel genotype (odds ratio, 2.81; 95% confidence interval, 1.32-5.99; P = .0073). In a subgroup of 167 mothers with data on prenatal intake of supplements containing folic acid (a synthetic form of folate), DHFR19bpdel-associated risk was elevated significantly only among those who reported taking folic acid supplements. Maternal MTHFR genotype was unrelated to the risk of having a child with retinoblastoma.

CONCLUSIONS

Maternal homozygosity for a polymorphism in the DHFR gene necessary for converting synthetic folic acid into biologic folate was associated with an increased risk for retinoblastoma. Prenatal ingestion of synthetic folic acid supplements may be associated with increased risk for early childhood carcinogenesis in a genetically susceptible subset of the population.

Perinatal characteristics and retinoblastoma

PURPOSE

The etiology of retinoblastoma remains poorly understood. In the present study, we examined associations between perinatal factors and retinoblastoma risk in California children.

METHODS

We identified 609 retinoblastoma cases (420 unilateral, 187 bilateral, and 2 with laterality unknown) from California Cancer Registry records of diagnoses 1988-2007 among children < 6 years of age. We randomly selected 209,051 controls from California birth rolls. The source of most study data was birth certificates. Multivariable logistic regression was used to examine associations between retinoblastoma and perinatal characteristics.

RESULTS

Bilateral retinoblastoma was associated with greater paternal age [for fathers over 35, crude odds ratio (OR) = 1.73, 95 % confidence interval (CI) 1.20, 2.47] and with twin births (OR = 1.93, 95 % CI 0.99, 3.79). Among unilateral cases, we observed an increased risk among children of US-born Hispanic mothers (OR = 1.34, 95 % CI 1.01, 1.77) while a decreased risk was observed for infants born to mothers with less than 9 years of education (OR = 0.70, 95 % CI 0.49, 1.00), a group that consisted primarily of mothers born in Mexico. We observed that maternal infection in pregnancy with any STD (OR = 3.59, 95 % CI 1.58, 8.15) was associated with bilateral retinoblastoma.

CONCLUSIONS

This study supports the findings of previous investigations reporting associations between parental age, HPV infection, and retinoblastoma.

Parental diet and risk of retinoblastoma resulting from new germline RB1 mutation

We conducted a case-control study of sporadic bilateral retinoblastoma, which results from a new germline RB1 mutation, to investigate the role of parents' diet before their child's conception. Parents of 206 cases from nine North American institutions and 269 controls participated; of these, fathers of 184 cases and 223 controls and mothers of 204 cases and 260 controls answered a food frequency questionnaire administered by phone about their diet in the year before the child's conception. Cases provided DNA for RB1 mutation testing. We assessed parents' diet by examining 19 food groups. Father's intake of dairy products and fruit was associated with decreased risk and cured meats and sweets with increased risk. Mother's intake was not associated with disease for any food group. Considering analyses adjusted for the other food groups significantly associated with disease, energy intake, and demographic characteristics as well as more fully adjusted models, the associations with father's dairy products and cured meat intake were the most robust. In the fully adjusted, matched analysis, the odds ratios per daily serving were 0.70 (95% confidence interval (CI) 0.49-1.00, P = 0.047) for dairy products and 5.05 (CI 1.46-17.51, P = 0.01) for cured meat. The pattern of associations with paternal but not maternal diet is consistent with the fact that 85% of new germline RB1 mutations occur on the father's allele. As few human data exist on the role of diet in any condition resulting from new germ-cell mutation, additional studies will be needed to replicate or refute our findings.

Are children with birth defects at higher risk of childhood cancers?

Birth defects may influence the risk of childhood cancer development through a variety of mechanisms. The rarity of both birth defects and childhood cancers makes it challenging to study these associations, particularly for the very rare instances of each. To address this limitation, the authors conducted a record linkage-based cohort study among Texas children born between 1996 and 2005. Birth defects in the cohort were identified through the Texas Birth Defects Registry, and children who developed cancer were identified by using record linkage with Texas Cancer Registry data. Over 3 million birth records were included; 115,686 subjects had birth defects, and there were 2,351 cancer cases. Overall, children with a birth defect had a 3-fold increased risk of developing cancer (incidence rate ratio (IRR) = 3.05, 95% confidence interval (CI): 2.65, 3.50), with germ cell tumors (IRR = 5.19, 95% CI: 2.67, 9.41), retinoblastomas (IRR = 2.34, 95% CI: 1.21, 4.16), soft-tissue sarcomas (IRR = 2.12, 95% CI: 1.09, 3.79), and leukemias (IRR = 1.39, 95% CI: 1.09, 1.75) having statistically significant elevated point estimates. All birth defect groups except for musculoskeletal had increased cancer incidence. Untangling the strong relation between birth defects and childhood cancers could lead to a better understanding of the genetic and environmental factors that affect both conditions.

Trilateral retinoblastoma

Trilateral retinoblastoma is the association of hereditary bilateral or unilateral retinoblastoma with a pineal neuroblastic tumour. We describe two cases of trilateral retinoblastoma from a total of 141 cases of retinoblastoma seen over an 8.5 year period. Both had a fatal outcome, with survival times of only 4 and 8 months respectively.

[Lack of biological exchange in assisted reproductive techniques]

There is a clear dividing line in the group of actions aimed at solving sterility, and the techniques aimed at generating embryos to be transferred to a womb. The dividing line is now clearly established by science. The growing alarm among paediatricians raised by the higher risk of malformations and diseases in children when generated in vitro, with respect to those normally engendered, is leading to the need to clearly establish the consequences of in vitro technologies and informing society in an honest way. Two types of lack of exchange of information, cellular and molecular, cause the detected defects. In the fi rst place it is clear that both gametes should recognize each other when adequately mature and in the appropriate natural environment. In vitro technologies force these conditions and either one or both gametes might be impaired and consequently negative effects for the child might be caused. In the second place both embryo and maternal womb are deprived of that early mother-child communication facilitating implantation.

Retinal tumor imaging and volume quantification in mouse model using spectral-domain optical coherence tomography

We have successfully imaged the retinal tumor in a mouse model using an ultra-high resolution spectral-domain optical coherence tomography (SD-OCT) designed for small animal retinal imaging. For segmentation of the tumor boundaries and calculation of the tumor volume, we developed a novel segmentation algorithm. The algorithm is based on parametric deformable models (active contours) and is driven by machine learning-based region classification, namely a Conditional Random Field. With this algorithm we are able to obtain the tumor boundaries automatically, while the user can specify additional constraints (points on the boundary) to correct the segmentation result, if needed. The system and algorithm were successfully applied to studies on retinal tumor progression and monitoring treatment effects quantitatively in a mouse model of retinoblastoma.

Incidence of New Tumor Formation in Patients with Hereditary Retinoblastoma Treated with Primary Systemic Chemotherapy: Is There a Preventive Effect?

PURPOSE

To report the incidence of new tumor formation in hereditary retinoblastoma patients treated with primary systemic chemotherapy.

DESIGN

Noncomparative retrospective case series.

PARTICIPANTS

Fifty-eight consecutive patients with hereditary retinoblastoma treated with primary systemic chemotherapy.

METHODS

The charts of 58 consecutive patients with hereditary retinoblastoma treated between January 1996 and August 2005 were reviewed. Data extracted included gender, age at diagnosis, family history of retinoblastoma, laterality of disease, tumors per eye, Reese-Ellsworth grouping of affected eyes, starting and ending dates for chemotherapy, number of cycles of chemotherapy, chemotherapy regimen, need for external beam radiotherapy and/or enucleation, and development and location (macula, midzone, and periphery) of new tumors after the start of systemic chemotherapy.

MAIN OUTCOME MEASURE

New tumor formation after treatment with primary systemic chemotherapy.

RESULTS

Of the 58 patients, 48 had bilateral involvement at diagnosis. Median age at diagnosis was 6.6 months. Thirteen patients had a positive family history. Of the eyes with tumor (n = 106) at diagnosis, 52 (49%) were in Reese-Ellsworth groups I to III, whereas 54 (51%) were in group IV or V. Seven patients (12%) with a median age of 1.6 months at diagnosis formed 36 new tumors in 11 eyes after the start of chemotherapy. Median time from initiation of chemotherapy to detection of the first new tumor was 3 months (range, 1-15). Cumulative incidence of new tumor formation at 2 years was 10+/-3%. An age of <6 months at diagnosis, family history of retinoblastoma, and Reese-Ellsworth grouping of I to III were found to correlate significantly with an increased incidence of new tumor formation (P<0.001, P<0.001, and P = 0.021, respectively). Median follow-up for all patients was 5 years (range, 1-10.1).

CONCLUSION

New tumors continue to form in patients with hereditary retinoblastoma despite treatment with primary systemic chemotherapy. Younger patients and those with a positive family history are more likely to have new tumors formed. However, chemotherapy may impact small previously undetected lesions by slowing their growth and facilitating later focal consolidation.

Parental age and risk of childhood cancers: a population-based cohort study from Sweden

BACKGROUND

Frequent germ line cells mutations were previously demonstrated to be associated with aging. This suggests a higher incidence of childhood cancer among children of older parents. A population-based cohort study of parental ages and other prenatal risk factors for five main childhood cancers was performed with the use of a linkage between several national-based registries.

METHODS

In total, about 4.3 million children with their parents, born between 1961 and 2000, were included in the study. Multivariate Poisson regression was used to obtain the incidence rate ratios (IRR) and 95% confidence interval (CI). Children <5 years of age and children 5-14 years of age were analysed independently.

RESULTS

There was no significant result for children 5-14 years of age. For children <5 years of age, maternal age were associated with elevated risk of retinoblastoma (oldest age group's IRR = 2.39, 95%CI = 1.17-4.85) and leukaemia (oldest age group's IRR = 1.44, 95%CI = 1.01-2.05). Paternal age was significantly associated with leukaemia (oldest age group's IRR = 1.31, 95%CI = 1.04-1.66). For central nervous system cancer, the effect of paternal age was found to be significant (oldest age group's IRR = 1.69, 95%CI = 1.21-2.35) when maternal age was included in the analysis.

CONCLUSION

Our findings indicate that advanced parental age might be associated with an increased risk of early childhood cancers.

Oxidants and ocular tumors

Serum superoxide dismutase and catalase assays were performed using spectrophotometry in 60 adults and children with benign or malignant tumors and in controls. There was a statistically significant difference in the antioxidative status of children with intraocular tumors (primary retinoblastoma) compared with children without tumors. The difference was not significant in adults. These enzymes may be of value in the early diagnosis of malignant intraocular tumor, especially retinoblastoma.

Genomic imprinting and assisted reproductive technology: connections and potential risks

Assisted reproductive technology (ART) has become the standard of care for the treatment of many types of infertility. As a result, the numbers of children born after ART worldwide has escalated dramatically, and attention has turned to the potential risks of these procedures to the health and development of the children. In addition to the well-established risks of multiple gestations, recent reports have suggested a link between ART and rare disorders of imprinting including Beckwith-Wiedemann syndrome and Angelman syndrome. Here we review molecular mechanisms of genomic imprinting, consider how ART procedures could influence imprinting of gametes and embryos, and review the reports connecting imprinting disorders to ART. We highlight the importance of long-term follow-up of children born after ART, and emphasize the need for an improved understanding of the mechanisms of imprinting at the molecular level so that methods to prevent disruption of this critical epigenetic process can be developed.

Fruit and Vegetable Intake during Pregnancy and Risk for Development of Sporadic Retinoblastoma

OBJECTIVE

Little is known about the causes of sporadic (noninherited) retinoblastoma. Rates seem to be somewhat higher among poorer populations in Mexico. Fruits and vegetables are important sources of carotenoids and folate. We examined whether decreased gestational maternal intake of fruits and vegetables may contribute to development of sporadic retinoblastoma.

METHODS

At the Instituto Nacional de Pediatria in Mexico City, we conducted a hospital-based case-control study to evaluate prenatal maternal diet. We examined dietary intake of fruits and vegetables of mothers of 101 children with retinoblastoma and 172 control children using a dietary recall questionnaire and published food nutrient content tables.

RESULTS

The reported number of mean daily servings of fruits and vegetables was lower among case mothers when compared with control mothers [vegetables: 2.28 in controls, 1.75 in cases (P < 0.01); fruits: 2.13 in controls, 1.59 in cases (P = 0.07)]. Mean daily maternal folate intake from both vegetables and fruits was higher in controls (103 microg) than in cases (48 microg; P < 0.05). Risk for having a child with retinoblastoma was increased for mothers consuming fewer than 2 daily servings of vegetables [odds ratios (OR), 3.4; 95% confidence interval (95% CI), 2.0-6.0] or with a low intake of folate (OR, 3.9; 95% CI, 2.1, 7.3), or lutein/zeaxanthin (OR, 2.6; 95% CI, 1.5-4.6) derived from fruits and vegetables.

CONCLUSIONS

Decreased intake of vegetables and fruits during pregnancy and the consequent decreased intake of nutrients such as folate and lutein/zeaxanthin, necessary for DNA methylation, synthesis, and retinal function, may increase risk for having a child with sporadic retinoblastoma.

In vitro fertilization and childhood retinoblastoma

AIMS

To estimate the frequency of childhood retinoblastoma among children conceived by in vitro fertilization (IVF).

METHODS

Using the United Kingdom-based General Practice Research Database (GPRD), we identified all live births, cases of retinoblastoma and IVF procedures occurring between January 1989 and December 2001.

RESULTS

We identified 0 cases of retinoblastoma among 176 children conceived by IVF (Risk = 0/176, one-sided 97.5% CI 0, 0.02) and 24 cases of retinoblastoma diagnosed before age 5 years among 358,094 children not conceived by IVF (6.7 cases per 100,000 births [95% CI 4.5, 10]).

CONCLUSIONS

These data provide some reassurance that children born as a result of IVF are not at markedly increased risk of retinoblastoma.

New retinoblastoma tumor formation in children initially treated with systemic carboplatin

PURPOSE

To determine the frequency and timing of new intraocular tumor formation in children with hereditary retinoblastoma initially treated with systemic carboplatin.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

This study included 34 children (57 eyes) with hereditary bilateral retinoblastoma initially treated with systemic carboplatin at the Robert M. Ellsworth Ophthalmic Oncology Center at NewYork-Presbyterian Hospital from 1994 through 2000.

MAIN OUTCOME MEASURES

New tumor formation after initial treatment with systemic carboplatin.

RESULTS

There were a total of 165 tumors in 57 eyes. There were 63 new tumors in 27 eyes (47%) after administration of systemic carboplatin, for a mean of 1.1 new tumors per eye. The mean patient age at time of new tumor presentation was 9 months, with 57% of new tumors developing within 4 months of carboplatin treatment. Kaplan-Meier analysis showed that children who were treated when younger than 6 months of age were more likely to have new tumors (60%) compared with those treated after 6 months of age (31%; P = 0.0182).

CONCLUSIONS

New intraocular tumors continue to develop after systemic carboplatin; most new tumors appeared within 4 months of treatment.

Unique insertional translocation in a childhood Wilms' tumor survivor detected when his daughter developed bilateral retinoblastoma

Retinoblastoma and Wilms' tumor are rare childhood embryonic tumors associated with loss or inactivation of tumor suppressor genes, RB1 located within 13q14, and WT1 located within 11p13. Interchromosomal insertional translocations occur rarely, and such rearrangements within RB1 or WT1, even rarer. We report a unique family in which an insertional translocation of a chromosomal segment that included band 13q14 inserted into 11p13 caused childhood Wilms' tumor in the father, and whose child developed bilateral retinoblastoma. This is the first case of an insertional translocation that caused both tumors. This insertional translocation had significant consequences for genetic counseling and in utero diagnosis. The estimated risk for an offspring of this father to develop Wilms' tumor is up to 50%, to develop retinoblastoma up to 25%, to have neither tumor 25%, and to have both tumors 0%.

Incidence of retinoblastoma in children born after in-vitro fertilisation

Every year, 3000 women in the Netherlands are treated with in-vitro fertilisation (IVF), and results from studies suggest that the offspring of these women do not have a heightened risk of cancer. Between November, 2000, and February, 2002, we diagnosed retinoblastoma in five patients born after IVF. To calculate the relative risk of the disease, we assumed that the proportion of children conceived by IVF in the Netherlands is between 1.0 and 1.5%, and that the five patients who we diagnosed with the disease represent all new cases in the Netherlands during that period. Relative risks for retinoblastoma were significantly raised (7.2 [95% CI 2.4-17.0], and 4.9 [1.6-11.3], for 1% and 1.5% rates, respectively). This possible association of an increased risk of retinoblastoma in a population-based study needs to be established.

Case-control study of parental age, parity and socioeconomic level in relation to childhood cancers

BACKGROUND

Parental ages, parity, and social class have been found in some studies to be associated with particular childhood cancers. Further investigation is warranted because of conflicting findings, biases, and the need to test specific hypotheses.

METHODS

A case-control study was conducted (England and Wales, ages 0-14 years). Cases were ascertained from the National Registry of Childhood Tumours, and were born and diagnosed during 1968-1986. Birth record controls were matched 1:1 to cases on date of birth, sex and area. Information on variables of interest for both groups came from birth records. In all, 10 162 pairs could contribute to matched analyses.

RESULTS

The odds ratio (OR) for retinoblastoma resulting from assumed new germ cell mutations among children of fathers aged > or =45 years was 3.0 (95% CI : 0.2-41.7). The risk of childhood acute lymphoblastic leukaemia (ALL) was significantly higher among children of older mothers and fathers, and significant trends with increasing mothers' (P < 0.001) and fathers' (P = 0.002) ages were found. There was a strong and significant protective effect of increasing parity on risk of childhood ALL. The adjusted OR for parity of > or =5 (versus 0) was 0.5 (95% CI : 0.3-0.8). Children in more deprived communities had a lower risk of ALL; but this was not significant after confounders were allowed for. There was no significant effect of social class based on parental occupation on ALL risk, but the numbers were small in those analyses.

CONCLUSIONS

The associations between ALL and parental ages did not disappear when children with Down syndrome were excluded, suggesting an additional explanation beyond known links. The strong ALL association with parity may be because of an unknown environmental risk factor.

Intraocular surgery after treatment of retinoblastoma

OBJECTIVES

To analyze the results of intraocular surgery in patients treated for retinoblastoma and to assess the ocular and systemic outcomes.

DESIGN

Retrospective noncomparative case series.

PATIENTS

Forty-five consecutive patients who underwent an introcular surgery after treatment for retinoblastoma.

MAIN OUTCOME MEASURES

(1) Recurrence of retinoblastoma, (2) need for enucleation, and (3) systemic metastasis. Overall outcome was defined as favorable in the absence of any of these measures and unfavorable in the presence of 1 or more.

RESULTS

Thirty-four patients (76%) underwent a single procedure of cataract surgery, a scleral buckling procedure, or pars plana vitrectomy and 11 (24%) underwent a combination of 2 or more surgical procedures. In all, 16 patients (36%) achieved final visual acuity better than 20/200. Unfavorable outcomes included recurrence of retinoblastoma in 14 patients (31%), enucleation in 16 (36%), and systemic metastasis in 3 (7%). Five patients (20%) who underwent cataract surgery, 5 (63%) who underwent a scleral buckling procedure, and 9 (75%) who underwent pars plana vitrectomy manifested an unfavorable outcome. The median interval between completion of treatment for retinoblastoma and intraocular surgery was 26 months in patients with a favorable outcome vs 6 months in those with an unfavorable outcome.

CONCLUSIONS

Intraocular surgery after treatment for retinoblastoma may be justified in certain exceptional clinical situations. Cataract surgery is safe and effective in most cases. However, the need for a scleral buckling procedure and pars plana vitrectomy may be associated with a higher risk for recurrence of retinoblastoma, enucleation, and systemic metastasis, and a cautious approach is warranted.

Presence of human papilloma virus in tumor tissue from children with retinoblastoma: an alternative mechanism for tumor development

Epidemiological studies have shown that the use of barrier methods of contraception is associated with a decreased incidence of papilloma virus infection and reduced risk of having a child with retinoblastoma. Thirty-nine primary retinoblastomas were analyzed for the presence of papilloma virus sequences. Tumor tissue sections were also used to assess the expression of the retinoblastoma protein and proliferative index. Papilloma sequences were detected in 14 of 39 (36%) tumors. Tumors in which viral sequences were detected were associated with a lower proliferative index (68% versus 78%; P = 0.015). Children with tumors containing viral sequences had a lower risk of extraocular disease (odds ratio, 9.0; 95% confidence interval, 1.6-49; P = 0.008) and a lower birth weight (2.9 versus 3.5 kg; P = 0.030). Based on these data, it is our hypothesis that papilloma viruses may play a role in the development of sporadic retinoblastoma. Detection of papilloma virus sequences and retinoblastoma protein in certain primary lesions suggests an alternative mechanism of tumor development for sporadic retinoblastoma.

Is sunlight an aetiological agent in the genesis of retinoblastoma?

The incidence of unilateral, but not bilateral, retinoblastoma in human populations at different geographical locations increases significantly with ambient erythemal dose of ultraviolet B radiation from sunlight. This supports the hypothesis that sunlight plays a role in retinoblastoma formation.

The role of cyclin E in cell proliferation, development and cancer

Normal cell proliferation is under strict regulation governed by checkpoints located at distinct points in the cell cycle. The deregulation of these checkpoint events and the molecules associated with them may transform a normal cell into a cancer cell. One of these checkpoints whose deregulation results in transformation occurs at the Restriction point, near the G1/S boundary. The periodic appearance of one of the recently identified regulatory cyclins, cyclin E, coincides precisely with the timing of the Restriction point. The deregulation in the expression and activity of cyclin E has been associated with a number of cancers and is thought to be involved in the process of oncogenesis. In this chapter, we summarise the current knowledge on the regulation and apparent function of cyclin E in normal proliferating cells and in developing tissue and alterations of these processes in cancer.

Incomplete penetrance of familial retinoblastoma linked to germ-line mutations that result in partial loss of RB function

To study the molecular basis for the clinical phenotype of incomplete penetrance of familial retinoblastoma, we have examined the functional properties of three RB mutations identified in the germ line of five different families with low penetrance. RB mutants isolated from common adult cancers and from classic familial retinoblastoma (designated as classic RB mutations) are unstable and generally do not localize to the nucleus, do not undergo cyclin-dependent kinase (cdk)-mediated hyperphosphorylation, show absent protein "pocket" binding activity, and do not suppress colony growth of RB(-) cells. In contrast, two low-penetrant alleles (661W and "deletion of codon 480") retained the ability to localize to the nucleus, showed normal cdk-mediated hyperphosphorylation in vivo, exhibited a binding pattern to simian virus 40 large T antigen using a quantitative yeast two-hybrid assay that was intermediate between classic mutants (null) and wild-type RB, and had absent E2F1 binding in vitro. A third, low-penetrant allele, "deletion of RB exon 4," showed minimal hyperphosphorylation in vivo but demonstrated detectable E2F1 binding in vitro. In addition, each low-penetrant RB mutant retained the ability to suppress colony growth of RB(-) tumor cells. These findings suggest two categories of mutant, low-penetrant RB alleles. Class 1 alleles correspond to promoter mutations, which are believed to result in reduced or deregulated levels of wild-type RB protein, whereas class 2 alleles result in mutant proteins that retain partial activity. Characterization of the different subtypes of class 2 low-penetrant genes may help to define more precisely functional domains within the RB product required for tumor suppression.

Genomic imprinting of the human serotonin-receptor (HTR2) gene involved in development of retinoblastoma

Epidemiological and genetic studies of retinoblastoma (RB) suggested that imprinted genes might be genetically linked to the RB gene. In this study, we found that the human serotonin-receptor, HTR2, gene, which had been mapped nearby the RB gene on chromosome 13, was expressed only in human fibroblasts with a maternal allele and not in cells without a maternal allele. The 5' genomic region of the human HTR2 gene was cloned by PCR-mediated method. Only the 5' region of the gene was methylated in cells with the maternal gene, and it was not methylated in cells without the maternal gene. A polymorphism of PvuII site of the gene was also found and useful for the segregation analysis in a family of a RB patient and for analysis of loss of heterozygosity on chromosome 13 in tumor and its parental origin. These results suggest that the human HTR2 gene might be affected by genomic imprinting and that exclusive expression of the maternal HTR2 gene may be associated with the delayed occurrence of RB, which had lost the maternal chromosome 13.

New and recurrent tumors in germinal retinoblastoma: is there a treatment effect?

Patients with germinal retinoblastoma (those with bilateral disease or positive family history) have a mutation which puts them at risk for developing new tumors. It is unclear whether the frequency of new tumor development is effected by the type of treatment employed. It may be hypothesized that external beam radiation "sterilizes' the whole retina, and thus decreases the risk of new and recurrent tumors. We reviewed our experience with 66 eyes in 47 patients over the past ten years. We did not find a significant difference in the incidence of new and recurrent retinoblastoma among eyes treated with external beam radiation versus focal modalities.

Early stage of human adenovirus type 12-inoculated retinal tissue of F344 newborn rat

To elucidate the pathogenesis of adenovirus type 12 (Ad12)-induced rat retinal tumor, an experimental animal model of human retinoblastoma (RB), DNA analysis, in situ hybridization and immunohistochemistry were performed. The adenovirus oncogene E1A was detected in the host genome by Southern blot hybridization. Examined retinal tissues did not show any histological changes, but the number of retinal cells immunoreactive with an antibody to proliferating cell nuclear antigen (PCNA) increased with the course of study. In in situ hybridization, E1A gene expression was recognized at the inner granular layer of the retina at an early stage after virus inoculation, and subsequently, N-myc gene expression was recognized at the same region. No alteration was found in the retinoblastoma susceptibility gene (Rb gene) expression. The product of the virus oncogene integrated into the host genome could induce an increase in N-myc expression, without any abnormality of the Rb gene itself. Results from the present study could be useful in clarifying the tumorigenesis of this experimental model.

Intraocular retinoblastoma presenting as ocular and orbital inflammation

In the pediatric population, retinoblastoma must be included in the differential diagnosis of intraocular or orbital inflammation, especially if the case is atypical of unresponsive to medical therapy. Diffuse infiltrating retinoblastoma, a rare subtype of retinoblastoma, often presents as unilateral intraocular inflammation, usually occurs in older children, and may contain insufficient calcification for detection by CT scan. Orbital inflammatory signs may also be associated with intraocular retinoblastoma. The clinician must perform a thorough ocular examination in these cases with the suspicion of retinoblastoma. He or she must also understand the subtleties of noninvasive imaging in such cases. The goal is to diagnose this tumor more accurately and expediently so that treatment and counseling can be provided without delay.

Multiple changes in oncogenes and tumor suppressor genes in human retinoblastoma

PURPOSE

To present data to support the hypothesis that human retinoblastoma tumors form by a multistep process.

METHODS

Survey of the karyotype of 90 human retinoblastomas, with emphasis on changes in chromosomal regions known to contain oncogenes and tumor suppressor genes.

CONCLUSION

The data support the hypothesis that retinoblastoma occurs after multiple and often varied steps, similar to other human malignancies.

Asynchronous bilateral retinoblastoma: the St. Jude Children's Research Hospital experience

Between May 1962 and July 1993, 172 children presented at the St. Jude Children's Research Hospital for evaluation and/or treatment of retinoblastoma (RB). Of these, 65 presented with bilateral disease, while 107 had unilateral tumors. Of these 107 patients, nine subsequently developed RB in the unaffected eye. Initial age at diagnosis of these nine patients ranged from 3 weeks to 24 months (median = 2 months); five of the nine had a family history of RB at the time of initial diagnosis and one patient, without a family history of RB, presented with unilateral multiple tumors indicating inheritance of a germinal mutation and increased risk of RB development in the companion eye. Time to development of companion eye RB was 1-61 months postinitial diagnosis. Treatment of the initial eye included enucleation (n = 4), chemotherapy (n = 3), irradiation (n = 7), or a combination of these three modalities. Reese-Ellsworth grouping of the companion eye disease included I A (n = 7), III A (n = 1), and IV A (n = 1). Treatment of the second affected eye included irradiation in seven patients, cryotherapy in four, and chemotherapy in three. No companion eye has required enucleation to date. At last followup, 14/18 eyes remain intact. There have been no cases of metastatic dissemination; however, one patient has developed a second malignant neoplasm outside the field of irradiation. Eight of the nine patients remain alive. This experience reinforces the need for close follow-up of patients diagnosed with unilateral RB, especially those with a family history of RB and those with unilateral multiple tumors.

Apoptosis or retinoblastoma: alternative fates of photoreceptors expressing the HPV-16 E7 gene in the presence or absence of p53

A transgenic mouse model for retinoblastoma was produced previously by directing SV40 T antigen expression to retinal photoreceptor cells using the promoter of the interstitial retinol-binding protein (IRBP) gene. This gene becomes active prior to the terminal differentiation of photoreceptors. Because T antigen-transforming activity is attributable, at least in part, to the inactivation of the retinoblastoma (pRb) and p53 tumor suppressor proteins, we addressed the role of p53 in the development of retinoblastoma in mice. Transgenic mice expressing HPV-16 E7 under the control of the IRBP promoter were generated to inactivate pRb in photoreceptors while leaving p53 intact. Rather than developing retinoblastomas, the retinas of these mice degenerate due to photoreceptor cell death at a time in development when photoreceptors are normally undergoing terminal differentiation. The dying cells exhibit the histological and ultrastructural features of apoptosis and contain fragmented DNA. p53 is required for the induction of apoptosis in this model, because mice expressing E7 in a p53 nullizygous background develop retinal tumors instead of undergoing retinal degeneration.

Molecular phenotype of simian virus 40 large T antigen-induced primitive neuroectodermal tumors in four different lines of transgenic mice

BACKGROUND

We compared the molecular phenotypes of central nervous system tumors arising in four different lines of transgenic mice (TGM) carrying the Simian virus 40 large T antigen driven by different promoters or enhancers. Two of the four lines developed primitive neuroectodermal tumors (PNETs) in the brain stem or pineal gland. A third TGM line developed retinoblastomas (a PNET-like tumor of the retina) as well as PNETs in the mesencephalon, while the fourth TGM developed retinoblastomas and adrenal pheochromocytomas.

EXPERIMENTAL DESIGN

The expression of developmentally regulated polypeptides specific for the neuronal or glial lineage was examined in these PNETs using immunohistochemistry and Western blotting.

RESULTS

Neoplastic cells in all of the PNETs exhibited neuronal, but no glial specific markers as evidenced by the invariable expression of synaptophysin, but no detectable glial fibrillary acidic protein or myelin basic protein. PNETs with a more differentiated neuronal phenotype expressed multiple neuronal polypeptides. The phenotypic properties of these PNETs closely resembled those found in human brain PNET biopsy samples and cell lines derived therefrom.

CONCLUSIONS

We conclude that Simian virus 40 T antigen-induced PNETs in TGM exhibit the molecular phenotype of developing neurons or neuronal progenitor cells. Although many factors could influence the phenotype of these experimental PNETs (e.g., promoter, site of integration of the transgene) these PNETs appear to be suitable TGM models of human PNETs of the central nervous system.

Mechanisms of oncogenesis in patients with familial retinoblastoma

In an analysis of mutations in the RB1 gene in three patients, selected at random, who had a positive family history of tumours, we identified mutations, in constitutional cells, involving exons 3, 13 and 17 of the RB1 gene. We used SSCP and PCR sequencing to screen affected individuals and other members of their families. In two cases the mutations were 2 bp and 1 bp deletions identified in exons 3 and 17 respectively. The third mutation was a 1 bp insertion in exon 13. All three mutations lead to the generation of downstream premature stop codons as a result of frameshift changes, although the mutation in exon 3 possibly affects the splicing mechanism. The sites within the RB1 gene where these mutations occur contain interspersed repetitive DNA sequences, direct and inverted repeat sequences and/or dyad symmetrical elements suggesting that these areas promote the appropriate local sequence environment for the generation of deletions and insertions in the RB1 gene.