title: Hierarchy in somatic mutations arising during genomic evolution and progression of follicular lymphoma.
abstract: Follicular lymphoma (FL) is currently incurable using conventional chemotherapy or immunotherapy regimes, compelling new strategies. Advances in high-throughput sequencing technologies that can reveal oncogenic pathways have stimulated interest in tailoring therapies toward actionable somatic mutations. However, for mutation-directed therapies to be most effective, the mutations must be uniformly present in evolved tumor cells as well as in the self-renewing tumor-cell precursors. Here, we show striking intratumoral clonal diversity within FL tumors in the representation of mutations in the majority of genes as revealed by whole exome sequencing of subpopulations. This diversity captures a clonal hierarchy, resolved using immunoglobulin somatic mutations and IGH-BCL2 translocations as a frame of reference and by comparing diagnosis and relapse tumor pairs, allowing us to distinguish early versus late genetic eventsduring lymphomagenesis. We provide evidence that IGH-BCL2 translocations and CREBBP mutations are early events, whereas MLL2 and TNFRSF14 mutations probably represent late events during disease evolution. These observations provide insight into which of the genetic lesions represent suitable candidates for targeted therapies.
authors.affiliation: Division of Oncology, Department of Medicine, Stanford University, Stanford, CA 94305, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Green
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gentles
authors.forename: Ramesh V
authors.initials: RV
authors.lastname: Nair
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Irish
authors.forename: Shingo
authors.initials: S
authors.lastname: Kihira
authors.forename: Chih Long
authors.initials: CL
authors.lastname: Liu
authors.forename: Itai
authors.initials: I
authors.lastname: Kela
authors.forename: Erik S
authors.initials: ES
authors.lastname: Hopmans
authors.forename: June H
authors.initials: JH
authors.lastname: Myklebust
authors.forename: Hanlee
authors.initials: H
authors.lastname: Ji
authors.forename: Sylvia K
authors.initials: SK
authors.lastname: Plevritis
authors.forename: Ronald
authors.initials: R
authors.lastname: Levy
authors.forename: Ash A
authors.initials: AA
authors.lastname: Alizadeh
mesh_terms: D060965:Clonal Evolution / Q000235:genetics*; D002999:Clone Cells / Q000378:metabolism / Q000473:pathology; D004273:DNA, Neoplasm / Q000235:genetics*; D018450:Disease Progression; D059472:Exome / Q000235:genetics; D005787:Gene Frequency; D015894:Genome, Human / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D016130:Immunophenotyping; D008224:Lymphoma, Follicular / Q000235:genetics* / Q000473:pathology; D009154:Mutation / Q000502:physiology*; D059645:Mutation Rate; D016133:Polymerase Chain Reaction; D012008:Recurrence
chemical_list: D004273:DNA, Neoplasm