Integrative Genomic Analysis of Coincident Cancer Foci Implicates CTNNB1 and PTEN Alterations in Ductal Prostate Cancer

Marc Gillard, Justin Lack, Andrea Pontier, Divya Gandla, David Hatcher, Adam G. Sowalsky, Jose Rodriguez-Nieves, Donald Vander Griend, Gladell Paner, David VanderWeele*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Background: Ductal adenocarcinoma of the prostate is an aggressive subtype, with high rates of biochemical recurrence and overall poor prognosis. It is frequently found coincident with conventional acinar adenocarcinoma. The genomic features driving evolution to its ductal histology and the biology associated with its poor prognosis remain unknown. Objective: To characterize genomic features distinguishing ductal adenocarcinoma from coincident acinar adenocarcinoma foci from the same patient. Design, setting, and participants: Ten patients with coincident acinar and ductal prostate cancer underwent prostatectomy. Laser microdissection was used to separately isolate acinar and ductal foci. DNA and RNA were extracted, and used for integrative genomic and transcriptomic analyses. Outcome measurements and statistical analysis: Single nucleotide mutations, small indels, copy number estimates, and expression profiles were identified. Phylogenetic relationships between coincident foci were determined, and characteristics distinguishing ductal from acinar foci were identified. Results and limitations: Exome sequencing, copy number estimates, and fusion genes demonstrated coincident ductal and acinar adenocarcinoma diverged from a common progenitor, yet they harbored distinct alterations unique to each focus. AR expression and activity were similar in both histologies. Nine of 10 cases had mutually exclusive CTNNB1 hotspot mutations or phosphatase and tensin homolog (PTEN) alterations in the ductal component, and these were absent in the acinar foci. These alterations were associated with changes in expression in WNT- and PI3K-pathway genes. Conclusions: Coincident ductal and acinar histologies typically are clonally related and thus arise from the same cell of origin. Ductal foci are enriched for cases with either a CTNNB1 hotspot mutation or a PTEN alteration, and are associated with WNT- or PI3K-pathway activation. These alterations are mutually exclusive and may represent distinct subtypes. Patient summary: The aggressive subtype ductal adenocarcinoma is closely related to conventional acinar prostate cancer. Ductal foci contain additional alterations, however, leading to frequent activation of two targetable pathways. Ductal prostate cancer is enriched for PTEN alterations and hotspot mutations in CTNNB1. These are associated with activation of the PI3K and WNT signaling pathways, respectively, which are targetable pathways with inhibitors in clinical use and/or development.

Original languageEnglish (US)
Pages (from-to)433-442
Number of pages10
JournalEuropean Urology Focus
Volume5
Issue number3
DOIs
StateAccepted/In press - Jan 1 2018

Keywords

  • Coincident foci
  • CTNNB1 mutations
  • Ductal adenocarcinoma
  • PI3K pathway
  • Predictive biomarkers
  • Prostate cancer
  • PTEN alterations
  • WNT pathway

ASJC Scopus subject areas

  • Urology

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