Manuela A. Orjuela

Chromosomal Aberrations in Cord Blood Are Associated with Prenatal Exposure to Carcinogenic Polycyclic Aromatic Hydrocarbons

Molecular and traditional epidemiology studies have indicated a possible relationship between in utero environmental exposures and increased risk for childhood cancers, especially acute leukemias. Chromosomal aberrations have been associated with environmental exposures and cancer risk in adults. In order to more clearly define the association between prenatal exposures to carcinogenic polycyclic aromatic hydrocarbons (PAH) and chromosomal aberrations, chromosomal aberration frequencies were measured in a subset of 60 newborns from the Columbia Center for Childrens Environmental Health (CCCEH) Prospective Cohort Study. The subset was composed of African American and Dominican, nonsmoking mother-newborn pairs residing in low-income neighborhoods of New York City, who were exposed to varying levels of airborne PAHs. Prenatal exposure was assessed by questionnaire, personal air monitoring during the third trimester, and PAH-DNA adducts in umbilical cord blood. Chromosomal aberrations were measured in cord blood lymphocytes by fluorescence in situ hybridization. PAH-DNA adducts were not associated with chromosomal aberrations. However, airborne PAHs were significantly associated with stable aberration frequencies in cord blood (P < 0.01). Moreover, stable aberration frequencies were significantly higher among African American newborns compared with Dominican, despite no significant differences in PAH exposure. These results show for the first time an association between prenatal exposure to airborne carcinogenic PAHs and chromosomal aberrations in cord blood, suggesting that such prenatal exposures have the potential to cause cytogenetic damage that has been related to increased cancer risk in other populations. If confirmed, this finding may open new avenues for prevention.

Low-Dose Chemotherapy and Rituximab for Posttransplant Lymphoproliferative Disease (PTLD): A Children's Oncology Group Report

Optimal therapy for posttransplant lymphoproliferative disease (PTLD) remains problematic. A phase II trial adding rituximab to a low‐dose cyclophosphamide and prednisone regimen was conducted for pediatric patients with Epstein–Barr virus (EBV) (+), CD20 (+) PTLD. Fifty‐five patients were enrolled. Toxicity was similar for cycles of therapy containing rituximab versus those without. The complete remission (CR) rate was 69% (95% confidence interval (CI); 57%–84%). Of 12 patients with radiographic evidence of persistent disease at the end of therapy, eight were in CR 28 weeks later without further PTLD therapy. There were 10 deaths, 3 due to infections while receiving therapy and 7 from PTLD. The 2‐year event‐free survival (alive with functioning original allograft and no PTLD) was 71% (95% CI: 57%–82%) and overall survival was 83% (95% CI: 69%–91%) with median follow‐up of 4.8 years. Due to small numbers, we were unable to determine significance of tumor histology, stage of disease, allograft type or early response to treatment on outcome. These data suggest rituximab combined with low‐dose chemotherapy is safe and effective in treating pediatric with EBV (+) PTLD following solid‐organ transplantation.

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 μg) than in cases (48 μg; 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.

World disparities in risk definition and management of retinoblastoma: a report from the International Retinoblastoma Staging Working Group.

Following from the publication of the International Retinoblastoma Staging System, an open internet discussion group was created at the www.cure4kids.org resource. The results of a survey distributed among participants are discussed. Although most patients with retinoblastoma were treated under prospective protocols, there was a wide variation in the definition of risk criteria and in the criteria for giving adjuvant chemotherapy following enucleation. Definition of high‐risk histological features and the criteria for use of adjuvant therapy will be standardized in future studies. Internet meetings are a valuable mechanism for enabling participation from under‐resourced countries in the development of cooperative studies. Pediatr Blood Cancer 2008;50:692–694.

The association between benzo[a]pyrene-DNA adducts and body mass index, calorie intake and physical activity

Abstract Prior work suggests that body size and fat content may influence carcinogen-DNA adduct levels measured in white blood cells. Here we consider energy balance more broadly by assessing the impact of body mass index (BMI), physical activity and calorie intake on the presence of benzo[a]pyrene-DNA (BP-DNA) adducts in white blood cell DNA. Our cross-sectional study employed subjects from a separately conducted intervention trial. Physical activity and food intake data were collected at 12 and 15 months of follow-up, respectively. BP-DNA adducts were measured by high-performance liquid chromatography (HPLC) in white blood cell samples collected at 12 months of follow-up. Complete data on all variables were available from 143 subjects. Logistic regression showed that BMI was inversely associated with the presence of detectable adducts (OR = 0.90, p=0.02), and that hours of moderate-intensity physical activity were positively associated with the presence of detectable adducts (OR = 1.04, p=0.04). These results provide further evidence that body fat content influences carcinogen-DNA adduct levels, probably by altering the distribution of the lipophilic parent compound.

Blood Lead Levels in Mexico and Pediatric Burden of Disease Implications

BACKGROUND Although there has been success in reducing lead exposure with the phase-out of leaded gasoline, exposure to lead in Mexico continues to threaten the health of millions, much of which is from lead-based glazes used in pottery that leaches into food. OBJECTIVES An extensive historical review and analysis of available data on blood lead levels in Mexican populations was conducted. We used a calculated geometric mean to evaluate the effect of lead on the pediatric burden of disease. METHODS An extensive bibliographic search identified 83 published articles from 1978 to 2010 with blood lead level (BLL) data in Mexican populations representing 150 data points from more than 50,000 study participants. Values from these publications were categorized into various groupings. We then calculated the incidence of disease and disability-adjusted life-years resulting from these BLLs using the World Health Organizations burden of disease spreadsheets for mild mental retardation. RESULTS Reviewing all relevant studies, the geometric means of Mexican BLLs in urban and rural areas were found to be 8.85 and 22.24 ug/dL, respectively. Since the phase-out of leaded gasoline, the mean in urban areas was found to be 5.36 ug/dL and the average in rural areas is expected to be much higher. The U.S. Centers for Disease Control and Preventions (CDC) upper limit of blood lead in children under the age of 6 years is 5 ug/dL and the current U.S. average is 1.2 ug/dL. Our results indicate that more than 15% of the population will experience a decrement of more than 5 IQ points from lead exposure. The analysis also leads us to believe that lead is responsible for 820,000 disability-adjusted life-years for lead-induced mild mental retardation for children aged 0 to 4 years. CONCLUSION Lead continues to threaten the health of millions and remains a significant cause of disability in Mexico. Additional interventions in reducing or managing lead-based ceramic glazes are necessary to protect the public health.

Role of immunosuppression regimen in post-transplant lymphoproliferative disorder in pediatric heart transplant patients

BACKGROUND Post-transplant lymphoproliferative disorder (PTLD) contributes to morbidity and mortality after transplantation. We examined the effect of immunosuppressive regimen on the risk of developing PTLD after pediatric heart transplantation. METHODS The 324 pediatric heart transplant patients at 2 childrens hospitals were retrospectively reviewed for the primary outcome of PTLD development. Patient demographics, rejection frequency, serum cyclosporine and tacrolimus levels, induction therapy, donor and recipient Epstein-Barr virus, and cytomegalovirus serologic status were reviewed and comparisons made between immunosuppressive regimens. Comparisons were also made between transplantation in the early (1984-1995) and late (1996-2008) eras to help account for changes in clinical protocols that occurred during the study period. RESULTS PTLD developed in 33 (10%), of whom 109 (34%) were treated with tacrolimus. PTLD developed in 15% of those treated with tacrolimus compared with 8% of patients treated solely with cyclosporine. Tacrolimus use was a significant predictor of PTLD, with a hazard ratio [HR] of 4.04 (95% confidence interval [CI], 2.03-8.02; p = 0.0001). Neither Epstein-Barr virus, cytomegalovirus donor/recipient status, nor gender predicted PTLD development. Younger age at transplant, higher rejection frequency, and induction therapy predicted PTLD development by univariate analysis. Multivariate modeling demonstrated that tacrolimus use (HR, 7.03; 95% CI, 2.87-17.2; p < 0.001) remained an independent predictor of PTLD, when controlling for age, era of transplantation, induction therapy, and rejection frequency. CONCLUSIONS This study suggests the use of tacrolimus after pediatric heart transplantation is independently associated with an increased risk of PTLD compared with cyclosporine alone.

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

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.

Preliminary studies on the effect of moderate physical activity on blood levels of glutathione.

Abstract Molecular epidemiological approaches are being used to study how physical activity may protect against cancer. Prior epidemiological data suggest that physical activity protects against lung cancer; however, interpretation of these data is complicated by potential confounding by smoking. Glutathione (GSH) detoxifies cigarette smoke carcinogens and the paper tests whether physical activity levels are associated with blood GSH levels. Study subjects were enrolled in a chemoprevention trial testing whether antioxidant micronutrient supplementation reduces genetic damage from cigarette smoking. Physical activity data were collected by questionnaire from 178 subjects at 12 months of follow-up in the trial. Total GSH (tGSH), which is the sum of free and protein-bound GSH and glutathione disulfide levels, was measured using the 5,5′-dithiobis-(2-nitrobenzenoic acid) colormetric assay with red blood cell samples collected at the 12-month time point. In multivariate linear regression analyses that controlled for gender and cigarettes smoked per day, tGSH was positively associated with hours per week of moderate intensity activity (β=0.005, p=0.02). Hours per week of vigorous intensity activity were unassociated with tGSH and the effect of moderate activity remained after control for vigorous activity. The results are consistent with prior research showing differential effects of moderate and vigorous activity and suggest a mechanism through which physical activity may influence lung cancer risk.

Prenatal PAH Exposure is Associated with Chromosome-specific Aberrations in Cord Blood

Chromosomal aberrations are associated with increased cancer risk in adults. Previously, we demonstrated that stable aberrations involving chromosomes 1-6 in cord blood are associated with prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) measured in air and are disproportionate to genomic content. We now examine whether the association with air PAHs is chromosome-specific and extends to smaller chromosomes. Using whole chromosome paints for chromosomes 1-6, 11, 12, 14 and 19, and a 6q sub-telomere specific probe, we scored 48 cord bloods (1500 metaphases per sample) from newborns monitored prenatally for airborne PAH exposure in the Columbia Center for Childrens Environmental Health cohort. Frequencies of stable aberrations were calculated as incident aberrations per 100 cell equivalents scored, and examined for association with airborne PAHs. Aberrations in chromosome 6 occurred more frequently than predicted by genomic content (p<0.008). Levels of both prenatal airborne PAHs and stable aberration frequency in chromosomes 1-6 decreased to half the levels reported previously in the same cohort (mean PAH decreased from 3.6 to 1.8ng/m(3); mean stable aberration frequency from 0.56 to 0.24, SD=0.19). The mean stable aberration frequency was 0.45 (SD=0.15) in chromosomes 11-19. After adjusting for gender, ethnicity, and household smokers, the mean stable aberration frequency increased with increasing PAH exposure: with a doubling of prenatal PAH exposure, the mean stable aberration frequency for the chromosome1-6 group increased by a factor of 1.49 (95% CI: 0.84, 2.66; p=0.17); for chromosomes 11-19 mean stable aberration frequency increased by 2.00 (95% CI: 1.11, 3.62; p=0.02); for chromosome 6 alone, it increased by 3.16 (95% CI: 0.93, 10.77; p=0.06); there was no increase for chromosomes 1-5 (p>0.8). Aberrations in chromosomes 11, 12, 14, 19 and 6 were associated with prenatal exposure to PAHs in air, even at lower levels of PAH in air. The observed chromosome-specific effects of prenatal airborne PAHs raise concern about potential cancer risk.