Citations

AbstractObjectiveWhile prior Epstein–Barr virus (EBV) infection has been consistently associated with subsequent risk of developing multiple sclerosis (MS), the association with other common herpesviruses has been more controversial. Our objectives were to determine whether remote infection with EBV and other common herpesviruses affect the susceptibility to pediatric MS and if there are interactions between genetic and demographic factors and viral infections.MethodsCases with pediatric‐onset MS or clinically isolated syndrome within 4 years of disease onset, and controls were recruited from 16 American pediatric MS centers. Logistic regression models adjusted for potential confounders assessed the association between case status and serological evidence for past infection with EBV, cytomegalovirus (CMV), Herpes Simplex viruses‐1 (HSV‐1) and ‐2. We determined the heterogeneity of the effect of viral infection on the risk of having MS according to race, ethnicity and HLA‐DRB1:1501 status.ResultsA total of 356 pediatric cases and 493 controls were recruited. In multivariable models, EBV‐viral capsid antigen (VCA) seropositivity was associated with increased odds of having MS by 7.4 times (95% CI: 4.5–12.0, P < 0.001). Seropositivity for HSV‐1 was also associated with increased odds of having MS (OR 1.54, 95% CI: 1.06–2.25, P = 0.025) but this increase was seen only in Whites (OR = 2.18, 95% CI 1.35–3.52, P < 0.001) and those negative for HLA‐DRB1*1501 (OR = 1.89, 95% CI 1.17–3.03, P = 0.009). The effect of remote EBV infection on the risk of pediatric MS depended on race and HLA‐DRB1*15:01 status.InterpretationEBV seropositivity is strongly associated with pediatric MS, as is HSV‐1 seropositivity in subjects negative for HLA‐DRB1*15:01. Our report of interactions between select viral exposures, and age, race and DRB1 status suggests a complex effect of environmental and genetic risk factors on MS development.

10571 Background: Pediatric medulloblastoma patients exposed to craniospinal radiation (CSI) are at high risk of developing endocrinopathies, including hypothyroidism. We sought to evaluate the role of genetic variation on hypothyroidism susceptibility among survivors of pediatric medullobastoma. Methods: Records from 61 medulloblastoma survivors treated at Texas Children’s Hospital between 1997 and 2013 were reviewed. All patients completed baseline and yearly follow-up thyroid assessments. Genome-wide genotyping was performed on Illumina HumanOmni1 and HumanOmni2.5 BeadChip single nucleotide polymorphism (SNP) arrays. Following standard quality control measures and exclusion of rare variants (minor allele frequency [MAF] < 5%), 572,562 autosomal SNPs were included in our analyses. The association between each SNP and hypothyroidism was tested using Fisher’s exact test and logistic regression, assuming additive allelic effects. Results: A total of 25 patients (41%) developed hypothyroidism with median follow-up of 8.3 years from diagnosis (range: 1.8-17.2 years). Primary hypothyroidism was identified in 9 (36%) cases, while the remaining 16 (64%) developed central hypothyroidism. Hypothyroidism was detected in 13 of 40 (33%) individuals exposed to < 30 Gy CSI and 12 of 21 (57%) individuals exposed to ≥30 Gy CSI (p = 0.06). Genome-wide association analysis identified several risk loci, including 3 variants associated with hypothyroidism (p-value < 1x10-5) at chromosome 2q11.2 ( NPAS2 gene). The top overall SNP (MAF = 27.5%, p-value = 6.5x10-7) remained strongly associated with hypothyroidism after accounting for possible confounders, including CSI dose, CSI type (proton/photon), age, sex, and genetic ancestry. Conclusions: Our findings suggest susceptibility to treatment-related hypothyroidism is strongly influenced by common genetic variation in NPAS2. The NPAS2 gene, a central component of the circadian rhythm network, is a transcriptional activator and regulator of DNA damage response and DNA repair genes.

2068 Background: Pituitary carcinoma (PC) is a rare and aggressive neuroendocrine tumor diagnosed once a pituitary adenoma (PA) becomes metastatic. Although no standard treatment currently exists, surgery, radiation (XRT) and/or chemotherapy are most commonly used. Recently, treatment with temozolomide (TMZ) has shown promising results, although the lack of prospective trials limits accurate outcome assessment. Methods: We describe a single-center multidisciplinary team experience in managing PC patients over a 13-year period (Oct, 2003 to Jan, 2017). Results: A total of 17 patients (9 males) were seen. Median age at diagnosis of PC was 44 years (range 16-82 years) and the median time from PA to PC conversion was 6 years (range 1-29 years). Median follow-up time: 28 months (range 8-158 months) with 7 reported deaths. The majority of PC was hormone-secreting (HS) subtype (n = 12): ACTH (n = 5), PRL (n = 4), FSH/LH (n = 2), GH (n = 1). After PC diagnosis, all pituitary tumors were locally invasive, all underwent at least one resection (mean 2.3) and all received at least one course of XRT alone (IMRT = 76%, SRS = 29%, IMPT = 12%) or concurrent with chemotherapy (18%). Immunohistochemistry showed high Ki-67 labeling index ( > 3%) in 9 (53%) cases. Most cases (n = 14) had metastases to the CNS, 35% of those had combined CNS and systemic foci. Ten (59%) cases underwent focal treatment of metastases, 90% of which underwent XRT. The most common chemotherapy used was TMZ [n = 14 (82%): single agent (n = 10); TMZ+capecitabine (n = 5); concurrent TMZ+XRT (n = 3); concurrent TMZ+XRT with adjuvant TMZ (n = 1)]. The median longest progression-free survival (LPFS) was 18 months (range 4-45 months). TMZ was associated with the chemotherapy-related LPFS in 9 (75%) cases. The 2, 3 and 5 year survival rate was 65%, 53% and 35%, respectively. All patients surviving > 5 years were treated with TMZ (n = 5, 2 survived > 10 years). Two refractory cases are currently on PD-1 inhibitor agent. Eighty percent of non-functioning PC were alive at last follow-up (HS-PC, 58%). Recurrence occurred in 11 (65%) cases. Conclusions: Treatment of PC requires a multidisciplinary approach. Multimodality therapy with surgery, radiation and TMZ was associated with higher survival rates and longer PFS.

Purpose There are sparse data defining the dose response of radiation therapy (RT) to the hypothalamus and pituitary in pediatric and young adult patients with brain tumors. We examined the correlation between RT dose to these structures and development of endocrine dysfunction in this population. Materials and Methods Dosimetric and clinical data were collected from children and young adults (< 26 years of age) with brain tumors treated with proton RT on three prospective studies (2003 to 2016). Deficiencies of growth hormone (GH), thyroid hormone, adrenocorticotropic hormone, and gonadotropins were determined clinically and serologically. Incidence of deficiency was estimated using the Kaplan-Meier method. Multivariate models were constructed accounting for radiation dose and age. Results Of 222 patients in the study, 189 were evaluable by actuarial analysis, with a median follow-up of 4.4 years (range, 0.1 to 13.3 years), with 31 patients (14%) excluded from actuarial analysis for having baseline hormone deficiency and two patients (0.9%) because of lack of follow-up. One hundred thirty patients (68.8%) with medulloblastoma were treated with craniospinal irradiation (CSI) and boost; most of the remaining patients (n = 56) received involved field RT, most commonly for ependymoma (13.8%; n = 26) and low-grade glioma (7.4%; n = 14). The 4-year actuarial rate of any hormone deficiency, growth hormone, thyroid hormone, adrenocorticotropic hormone, and gonadotropin deficiencies were 48.8%, 37.4%, 20.5%, 6.9%, and 4.1%, respectively. Age at start of RT, time interval since treatment, and median dose to the combined hypothalamus and pituitary were correlated with increased incidence of deficiency. Conclusion Median hypothalamic and pituitary radiation dose, younger age, and longer follow-up time were associated with increased rates of endocrinopathy in children and young adults treated with radiotherapy for brain tumors.