Constitutional mismatch repair deficiency–associated brain tumors: report from the European C4CMMRD consortium

Abstract Background Malignant brain tumors (BT) are among the cancers most frequently associated with constitutional mismatch repair deficiency (CMMRD), a rare childhood cancer predisposition syndrome resulting from biallelic germline mutations in mismatch repair genes. This study analyzed data from the European "Care for CMMRD" (C4CMMRD) database to describe their clinical characteristics, treatments, and outcome with the aim of improving its diagnosis/treatment. Methods Retrospective analysis of data on patients with CMMRD and malignant BT from the C4CMMRD database up to July 2017. Results Among the 87 registered patients, 49 developed 56 malignant BTs: 50 high-grade gliomas (HGG) (with giant multinucleated cells in 16/21 histologically reviewed tumors) and 6 embryonal tumors. The median age at first BT was 9.2 years [1.1–40.6], with nine patients older than 18. Twenty-seven patients developed multiple malignancies (including16 before the BT). Most patients received standard treatment, and eight patients immunotherapy for relapsed HGG. The 3- and 5-year overall survival (OS) rates were 30% (95% CI: 19–45) and 22% (95% CI: 12–37) after the first BT, with worse prognosis for HGG (3-year OS = 20.5%). Six patients were alive (median follow-up 2.5 years) and 43 dead (38 deaths, 88%, were BT-related). Other CMMRD-specific features were café-au-lait macules (40/41), multiple BTs (5/15), developmental brain anomalies (11/15), and consanguinity (20/38 families). Conclusions Several characteristics could help suspecting CMMRD in pediatric malignant BTs: giant cells on histology, previous malignancies, parental consanguinity, café-au-lait macules, multiple BTs, and developmental brain anomalies. The prognosis of CMMRD-associated BT treated with standard therapies is poor requiring new therapeutic up-front approaches

Medulloblastomas with ELP1 pathogenic variants: A weakly penetrant syndrome with a restricted spectrum in a limited age window

Background: ELP1 pathogenic variants (PV) have been recently identified as the most frequent variants predisposing to Sonic Hedgehog (SHH) medulloblastomas (MB); however, guidelines are still lacking for genetic counseling in this new syndrome. Methods: We retrospectively reviewed clinical and genetic data of a French series of 29 ELP1-mutated MB. Results: All patients developed SHH-MB, with a biallelic inactivation of PTCH1 found in 24 tumors. Other recurrent alterations encompassed the TP53 pathway and activation of MYCN/MYCL signaling. The median age at diagnosis was 7.3 years (range: 3-14). ELP1-mutated MB behave as sporadic cases, with similar distribution within clinical and molecular risk groups and similar outcomes (5 y - OS=86%); no unusual side effect of treatments was noticed. Remarkably, a germline ELP1 PV was identified in all patients with available constitutional DNA (n=26); moreover, all tested familial trio (n=11) revealed that the PVs were inherited. Two of the 26 index cases from the French series had a family history of MB; pedigrees from these patients and from 1 additional Dutch family suggested a weak penetrance. Apart from MB, no cancer was associated with ELP1 PVs; second tumors reported in 4 patients occurred within the irradiation fields, in the usual time-lapse for expected radiotherapy-induced neoplasms. Conclusions: The low penetrance, the "at risk' age window limited to childhood and the narrow tumor spectrum, question the actual benefit of genetic screening in these patients and their family. Our results suggest restricting ELP1 germline sequencing to patients with SHH-MB, depending on the parents"request

MBCL-43 pronostic factors for overall survival after recurrence in childhood medulloblastoma

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Parental smoking, maternal alcohol, coffee and tea consumption and the risk of childhood brain tumours: the ESTELLE and ESCALE studies (SFCE, France)

International audiencePURPOSE: To investigate whether parental smoking around the time of pregnancy or maternal consumption of beverages (alcohol, coffee, or tea) during pregnancy were associated with the risk of CBT.METHODS: We pooled data from two French national population-based case-control studies with similar designs conducted in 2003-2004 and 2010-2011. The mothers of 510 CBT cases (directly recruited from the national childhood cancer register) and 3,102 controls aged under 15 years, frequency matched by age and gender, were interviewed through telephone, which included questions about prenatal parental smoking and maternal consumption of alcohol, coffee and tea. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression, adjusted for age, sex and study of origin.RESULTS: No association was seen between CBT and the mother smoking or drinking alcohol, coffee, or tea during the index pregnancy. The OR between CBT and paternal smoking in the year before birth (as reported by the mother) was 1.25 (95% CI 1.03, 1.52) with an OR of 1.09 (0.99, 1.19) for every 10 cigarettes per day (CPD) smoked. The association between paternal smoking and CBT appeared to be stronger in children diagnosed before the age of five years (OR 1.52, 95% CI 1.14, 2.02) and for astrocytoma (OR 1.86, 95% CI 1.26, 2.74).CONCLUSION: We found some evidence of a weak association between paternal smoking in the year before the child's birth and CBT, especially astrocytomas. These findings need to be replicated in other samples, using similar classifications of tumour subtypes

Factors related to pregnancy and birth and the risk of childhood brain tumours: The ESTELLE and ESCALE studies (SFCE, France)

International audienceLittle is known of the causes of childhood brain tumors (CBT). The aims of this study were to investigate whether extremes of birth weight were associated with increased risk of CBT and whether maternal preconceptional folic acid supplementation or breastfeeding reduced the risk. In addition, other maternal characteristics and birth related factors were also investigated. We pooled data from two French national population-based case-control studies with similar designs conducted in 2003–2004 and 2010–2011. The mothers of 510 CBT cases (directly recruited from the national childhood cancer register) and 3,102 controls aged under 15 years, frequency matched by age and gender did a telephone interview, which focussed on demographic and perinatal characteristics, and maternal life style habits and reproductive history. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression, adjusted for age, sex, study of origin and relevant confounders. No association was found between CBT and birth weight or fetal growth. The use of preconceptional folic acid supplementation was rare (5.3% in cases and 7.8% in controls) and the OR was 0.8 (95% CI 0.5, 1.4). There was no association with breastfeeding, even prolonged (six months or more; OR 1.0, 95% CI 0.8, 1.4). Neither was there any association between CBT and other investigated factors (maternal body mass index, gestational weight gain, congenital abnormality, maternal reproductive history or use of fertility treatments. Although large, this study was underpowered for subtype analyses. Pooling data with other population-based studies may provide further insight into findings by CBT subtypes

Prognostic Clinical and Biologic Features for Overall Survival after Relapse in Childhood Medulloblastoma

International audienceDespite progress in the biology and upfront treatment of childhood medulloblastoma, relapse is almost universally fatal. No standardized treatment has so far been established for these patients. By determining which characteristics are prognostic after relapse, treatment strategies may be optimized for each of these children. We demonstrated that molecular subgroup at diagnosis is a relevant prognostic factor of outcome after relapse. Moreover, we showed that time to relapse and the use of salvage radiotherapy at relapse might have a potential impact on post-relapse survival. Our data suggest that ongoing efforts toward a better understanding of the biology, timing and type of relapse would be important to understand the determinants of tumor behavior at relapse. This could help us address more specific questions on the best surveillance strategies after completion of the treatment and the introduction of risk-stratified second-line treatment strategies

Maternal residential pesticide use during pregnancy and risk of malignant childhood brain tumors: A pooled analysis of the ESCALE and ESTELLE studies (SFCE)

International audienceSome previous epidemiological studies have suggested that pesticide exposure during pregnancy may have a possible role in the development of childhood brain tumors (CBT). We pooled data from two French national population-based, case-control studies to investigate the association between maternal residential use of pesticides during pregnancy and the risk of CBT. The mothers of 437 CBT cases and 3,102 controls aged under 15 years who resided in France at diagnosis/interview, frequency-matched by age and gender, answered a structured telephone interview conducted by trained interviewers. Unconditional logistic regression was used to estimate pooled odds ratio (OR) and 95% confidence intervals (95% CI). CBT was significantly associated with the maternal home use of pesticides during pregnancy (OR 1.4, 95% CI 1.2-1.8) and, more specifically, with insecticide (OR 1.4, 1.2-1.8). We could not draw any conclusions about herbicides and/or fungicides because few women used them during pregnancy and most of these mothers also used insecticides. Although potential recall bias cannot be excluded, our findings of this pooled analysis support the hypothesis that residential maternal use of pesticides during pregnancy and particularly insecticides may increase the risk of CBT. Future investigations to verify these findings and to explore for CBT subtypes and dose-response are necessary to have a better understanding of the possible role of pesticides in etiology of CBT.</p