Abstract 1447: Investigating susceptibility to sporadic osteosarcoma by genome-wide copy number analysis

Abstract

Abstract Constitutional copy-number variants (CNVs) frequently overlap genomic regions that contain genes associated with cancer. In addition, copy number alterations (CNAs) in tumors often coincide with sites of CNVs and may arise through progression of CNVs. Osteosarcoma (OS), the most common human bone malignancy, can arise in familial or sporadic forms. While germline mutations of tumor suppressor genes have been implicated in a minority of OS cases, little is known about genetic changes that contribute to the etiology of sporadic OS. Using high-resolution SNP/CNV arrays, we observed a higher global germline CNV frequency in patients with sporadic OS compared to healthy controls. Given the early age of onset and the extensive constitutional CNVs, we hypothesize that these genomic alterations are linked to susceptibility to OS. Here we investigate whether specific constitutional CNVs are related to susceptibility to sporadic OS and whether OS tumor CNAs arise via progression of constitutional CNVs in these patients. Blood derived DNA samples from patients with sporadic OS with wild-type germline p53 sequence and gene dosage were selected for analysis on Affymetrix GW6.0 arrays with paired pre-therapy tumor biopsies. Initial results from a discovery set of samples (n=43 pairs) reveal a copy number loss at 1q43, in a region that overlaps several genes that have a role in bone formation, microtubules and cytoskeletal organization. This loss was present in 43% of the blood-derived DNA samples and 44% of the tumor-derived samples, whereas this variant was noted in only 1.2% of controls. Furthermore, the germline 1q43 deletion correlates with poor survival of the OS patients (p=0.04, Long Rank). Analysis of an independent validation set (n=32 pairs) is currently underway to confirm the initial finding and further characterize specific constitutional CNVs among sporadic OS patients. The findings of this study will open new avenues for the discovery of novel loci implicated in susceptibility to OS with potential for improved diagnostic and prognostic options as well as further insight into disease pathogenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1447. doi:1538-7445.AM2012-1447