Low-frequency variation near common germline susceptibility loci are associated with risk of Ewing sarcoma.

BACKGROUND: Ewing sarcoma (EwS) is a rare, aggressive solid tumor of childhood, adolescence and young adulthood associated with pathognomonic EWSR1-ETS fusion oncoproteins altering transcriptional regulation. Genome-wide association studies (GWAS) have identified 6 common germline susceptibility loci but have not investigated low-frequency inherited variants with minor allele frequencies below 5% due to limited genotyped cases of this rare tumor. METHODS: We investigated the contribution of rare and low-frequency variation to EwS susceptibility in the largest EwS genome-wide association study to date (733 EwS cases and 1,346 unaffected controls of European ancestry). RESULTS: We identified two low-frequency variants, rs112837127 and rs2296730, on chromosome 20 that were associated with EwS risk (OR = 0.186 and 2.038, respectively; P-value < 5×10-8) and located near previously reported common susceptibility loci. After adjusting for the most associated common variant at the locus, only rs112837127 remained a statistically significant independent signal (OR = 0.200, P-value = 5.84×10-8). CONCLUSIONS: These findings suggest rare variation residing on common haplotypes are important contributors to EwS risk. IMPACT: Motivate future targeted sequencing studies for a comprehensive evaluation of low-frequency and rare variation around common EwS susceptibility loci.

Genome-wide association study identifies multiple new loci associated with Ewing sarcoma susceptibility.

Ewing sarcoma (EWS) is a pediatric cancer characterized by the EWSR1-FLI1 fusion. We performed a genome-wide association study of 733 EWS cases and 1346 unaffected individuals of European ancestry. Our study replicates previously reported susceptibility loci at 1p36.22, 10q21.3 and 15q15.1, and identifies new loci at 6p25.1, 20p11.22 and 20p11.23. Effect estimates exhibit odds ratios in excess of 1.7, which is high for cancer GWAS, and striking in light of the rarity of EWS cases in familial cancer syndromes. Expression quantitative trait locus (eQTL) analyses identify candidate genes at 6p25.1 (RREB1) and 20p11.23 (KIZ). The 20p11.22 locus is near NKX2-2, a highly overexpressed gene in EWS. Interestingly, most loci reside near GGAA repeat sequences and may disrupt binding of the EWSR1-FLI1 fusion protein. The high locus to case discovery ratio from 733 EWS cases suggests a genetic architecture in which moderate risk SNPs constitute a significant fraction of risk.

Risk adapted chemotherapy for localised Ewing's sarcoma of bone: the French EW93 study.

AIM OF THE STUDY: To determine whether a risk factor adapted chemotherapy would improve the outcome of non-metastatic bone Ewing's sarcoma. METHODS: Standard risk tumours (SR, good histological response to chemotherapy or small unresected tumours) received the previous EW88 chemotherapy. Ifosfamide/etoposide (IE) were introduced after 3 courses of cyclophosphamide/doxorubicine when tumour regression was <50% or during consolidation therapy for the intermediate risk tumours (IR, intermediate histological response 5-30% residual cells or large unresected tumours >100ml). High risk tumours (HR, histological poor response >30% residual cells or clinical poor response <50% for unresectable tumours), received IE prior high dose busulfan/melphalan with stem cell rescue. RESULTS: From 1993 to 1999, 214 patients were enrolled. 5 y-EFS and OS were 60% (95% confidence interval (CI), 53-66) and 69% (95% CI, 63-75), respectively. 116 (54%), 46 (21%), 48 (22%) patients were considered as SR, IR and HR of relapse, respectively. No advantage to IE was observed in the IR group. As compared to previous study, tumour with poor histological response to induction chemotherapy seemed to benefit from the consolidation strategy including busulfan/melphalan: EFS were 45% (95% CI, 30-60) and 20% (95% CI, 7-43) for EW93 and EW88, respectively. Despite a risk-adapted strategy, histological response to chemotherapy remains the main prognostic factor in resected tumours, while initial tumour volume is the main prognostic factor for unresected tumours. CONCLUSION: These results showing a potential benefit of a consolidation strategy including busulfan/melphalan as compared to conventional chemotherapy needed confirmation by a randomised trial and were one of the bases of the ongoing EuroEwing99.

Efficacy of vinblastine in central nervous system Langerhans cell histiocytosis: a nationwide retrospective study.

BACKGROUND: Vinblastine (VBL) is the standard treatment for systemic Langerhans cell histiocytosis (LCH), but little is known about its efficacy in central nervous system (CNS) mass lesions. METHODS: A retrospective chart review was conducted. Twenty patients from the French LCH Study Group register met the inclusion criteria. In brief, they had CNS mass lesions, had been treated with VBL, and were evaluable for radiologic response. RESULTS: The median age at diagnosis of LCH was 11.5 years (range: 1-50). Intravenous VBL 6 mg/m2 was given in a 6-week induction treatment, followed by a maintenance treatment. The median total duration was 12 months (range: 3-30). Eleven patients received steroids concomitantly. Fifteen patients achieved an objective response; five had a complete response (CR: 25%), ten had a partial response (PR: 50%), four had stable disease (SD: 20%) and one patient progressed (PD: 5%). Of interest, four out of the six patients who received VBL without concomitant steroids achieved an objective response. With a median follow-up of 6.8 years, the 5-year event-free and overall survival was 61% and 84%, respectively. VBL was well-tolerated and there were no patient withdrawals due to adverse events. CONCLUSION: VBL, with or without steroids, could potentially be a useful therapeutic option in LCH with CNS mass lesions, especially for those with inoperable lesions or multiple lesions. Prospective clinical trials are warranted for the evaluation of VBL in this indication.