Despite considerable molecular heterogeneity, all diffuse gliomas are incurable at present, signaling an urgent need for improved understanding of glioma biology. Even with recent advances, functional and clinically relevant correlations between somatic and germline genetics in glioma remain virtually nonexistent. In particular, the extent to which any or all glioma risk alleles drive the development of somatically designated glioma subclasses is largely unknown. This proposal builds on our extensive collaborative experience with the germline characterization of glioma, and leverages an existing repository of sporadic glioma patients accrued from two of the nation's largest cancer centers (MD Anderson (MDA) and Memorial Sloan Kettering (MSK)). These resources ideally position us to examine the interaction of germline and somatic genetics in glioma evolution. Most existing large-scale profiling efforts, including those of the Cancer Genome Atlas (TCGA), lack extensive information on disease treatment and progression along with genome-wide germline polymorphism data. We propose to molecularly profile 1,350 cases from a set of over 2,000 glioma patients treated at our institutions with: 1) readily available tumor tissue; 2) stored germline DNA; and 3) detailed clinical data including treatment information, disease progression, and survival. Importantly, we have already obtained high- density germline single nucleotide polymorphism (SNP) data for these patients using the Illumina OncoArray platform. We now propose to conduct focused and comprehensive molecular profiling on tumor tissue ascertained from this patient cohort to correlate both glioma subclass and patterns of somatic alterations with germline risk alleles and clinical outcome measures. Our overall hypothesis is that glioma susceptibility alleles will correlate with distinct sets of somatic alterations and predict disease evolution and outcomes both between and within molecularly designated glioma subclasses. We propose the following specific aims:
Aim 1. Determine the spectrum of germline susceptibility alleles associated with molecularly and clinically distinct glioma subclasses.
Aim 2. Refine risk stratification by correlating germline susceptibility alleles with specific somatic alterations within individual glioma subclasses. Our findings should lead to significant innovation in how gliomas are conceptualized, from the perspectives for both molecular pathogenesis and patient management. Robust associations between germline genetics, molecular subclass, and somatic alterations will provide novel insights into how distinct tumor subtypes arise in specific patient populations and even point toward strategies for therapeutic development by identifying early-stage, pre-transformative sequences of molecular events. Moreover, these data could also enable targeted surveillance and early detection in at-risk populations, a management strategy that remains strikingly underexplored for glioma patients and, accordingly, has the potential to be paradigm-shifting.
The overall goal of this proposal is to identify interactions between germline risk SNPs, somatic mutations, and clinical outcomes. This study will molecularly subclassify glioma cases, and correlate SNP data (germline), whole exome sequencing (tumor ? somatic) and clinical outcomes to clarify the complex interplay between germline and somatic genetics and its influence over the biological behavior of diffuse gliomas. Such mechanistic insights will have significant therapeutic implications.
