180 likes | 387 Views
Acquisition of tumour multidrug resistance inevitable in most advanced solid tumours Failing to cure the majority of advanced solid tumours Declining therapeutic benefits at higher drug cost Drug resistance highly complex:
E N D
Acquisition of tumour multidrug resistance inevitable in most advanced solid tumours Failing to cure the majority of advanced solid tumours Declining therapeutic benefits at higher drug cost Drug resistance highly complex: Approx 10% of kinases alter resistance to one or more drugs (Swanton et al 2007 Cancer Cell ; Swanton et al 2007 Cell Cycle) Failure of Biomarker Validation 150,000 biomarkers only 100 for clinical use Predictive Biomarkers and Drug Resistance
Intratumour Heterogeneity • Evidence of intratumour heterogeneity • Possible Implications for biomarker studies • Practical approaches to address heterogeneity
Breast Cancer Intra-tumour HeterogeneitySector Ploidy Profiling and DNA Copy Number Analysis • Multiple intermixed cell subpopulations within one tumour differ by large genomic events/focal amplifications/ deletions Geyer and Reis-Filho J Path 2010 Shah and Aparicio Nature 2012 Navin N, et al. Genome Res 2010 Navin N, et al Nature 2011
Does a Single Tumour Biopsy: • Represent the tumour somatic/transcriptomic landscape ? • Provide robust biomarkers of outcome ? • Demonstrate that all mutations are ubiquitously present in every region of a tumour • Predicted by a linear/clonal sweep model of tumour evolution • Provide reliable data following Deep Sequencing Analysis to stratify patients for trials ?
Primary Mets Ubiquitous Shared Primary Shared Mets Private 65% mutations are heterogeneous and not present in every biopsy
Evidence for Convergent EvolutionSETD2 Loss of Function: H3K36 tri-methylation Normal 3 distinct SETD2 mutations associated with loss of function: Mutational capacity?
Evidence intratumour heterogeneity may impact upon drug response? • 6 weeks of Everolimus therapy • Assess status of mTOR pathway across different regions of the tumour • Evidence of Differential Pathway Activity post-Everolimus exposure?
Heterogeneous Kinase Domain mTOR mutation L2431P mTOR mutation L2431P
Kinase Domain mTOR mutation L2431P Associated with Constitutive Activation of the mTOR Kinase
Kinase Domain mTOR mutation L2431P Lies in A Repressor Domain Close to Activation Loop of Kinase
Tracking Tumour Growth R9 Normal Perinephric Metastasis Chest Wall Metastasis M1 M2a,b Seeding of metastatic sites can be tracked to one tumour region
Primary Tumour Regions Metastatic Sites Primary Tumour Regions Metastatic Sites Allelic Imbalance: ITH within Chest wall metastasis R9 Chest Wall Metastasis Perinephric Metastasis M2a,b M1 Only somatic mutations with >20x coverage were included Only somatic mutations with >20x coverage were included
Primary Tumour Regions Metastatic Sites Primary Tumour Regions Metastatic Sites Heterogeneity of RCC Prognostic Signature Expression Genes in ccB Median ccA 103 months ccB 24 months Genes upregulated in ccA Only somatic mutations with >20x coverage were included Only somatic mutations with >20x coverage were included
Relevance of ITH and Cancer Branched Evolution • Tumour Diversity Supports Evolutionary Fitness • (Maley et al 2006) • Tumour Adaptation and Selection for • Drug resistance (Su et al 2012; Lee et al 2011) • Metastatic growth (Yachidaand Campbell 2010, Shah 2009) • Tumour Sampling Bias • Different tumour biopsies different results • Sites of disease evolve independently • Clonal Dominance and Actionable Mutations? • Mutations present at one site but not another Patient 1