Extensive Regional Intra-Clonal Heterogeneity in Multiple Myeloma - Implications for Diagnostics, Risk Stratification and Targeted Treatment

摘要: INTRODUCTION In multiple myeloma (MM) samples for diagnostics, prognostication and response evaluation are most commonly obtained from the patients9 posterior iliac crest due to its accessibility safety, assuming a homogenous spread throughout bone marrow. However, imaging studies revealed highly imbalanced distribution of disease in majority patients, presenting with accumulations malignant plasma cells (PC) restricted areas marrow (BM), so called focal lesions (FL). line this pattern, our recently reported preliminary results paired FL random BM (RBM) strongly indicate an unequal sub-clones BM. Spatial genomic heterogeneity has not been systematically analyzed MM thus far, although existence would have high impact on interpretation drug resistance studies, risk stratification personalized treatment based markers. Here we report extended analysis regional RBM including 42 newly diagnosed 11 extensively treated patients 10 these also being studied longitudinally. MATERIAL & METHODS PCs were CD138-enriched. Leukapheresis products used as controls. For whole exome sequencing (WES) applied qXT kit SureSelect Clinical Research Exome bait design (Agilent). Paired-End was performed Illumina HiSeq 2500. Sequencing data aligned GRCh37/hg19 reference using BWA. Somatic single nucleotide variants (SNV) identified MuTect. Copy number aberrations (CNA) derived HumanOmni 2.5 bead chip ASCAT. Subclonal reconstruction SciClone. Gene expression profiles (GEP) generated Affymetrix U133plus2 microarrays. Statistical analyses carried out R software package 3.1.1. RESULTS detected median 86 (34 807) mutations per patient up 42% (median 5%) them unique specific site (non-ubiquitous). Among known driver genes, BRAF (n=2) KRAS (n=4) genes that often showed non-ubiquitous at baseline. , NRAS RB1 contributed one each. Furthermore, found temporal affecting ATR two associated poor outcome. Analyzing chromosomal prognostic value observed three site-specific del(1p) CDKN2C and/or FAM46C showing del(17p13). Non-ubiquitous gain(1q) or amp(1q) seen Of note, all cases event case baseline presented aberration subsequent samples. These observations support concept FLs sites resistant clones able cause relapse. four MYC translocation only site. longitudinal whom clone replaced by different translocation, indicating events locus secondary can be sub-clonal. contrast, primary IgH translocations always shared, confirming they initiating events. Paired discordant GEP profiles, further supporting (HR) clones. To investigate clinical relevance finding outcome 263 data. The 34 scores no significant differences compared HR both sites, suggesting drive prognosis even if ubiquitously present. CONCLUSIONS We show spatial is common MM. highlights importance accurate prediction, detection suitable targets precision medicine identification contributing resistance. As result recommend include examinations into routine diagnostics follow-up Disclosures Ashby: University Arkansas Medical Sciences: Employment. Barlogie: Signal Genetics: Patents Royalties. Davies: Celgene: Consultancy, Honoraria; Takeda: Janssen: Honoraria. Morgan: Univ AR Employment; Funding; Honoraria, Bristol Meyers: