title: Next-generation sequencing identifies germline MRE11A variants as markers of radiotherapy outcomes in muscle-invasive bladder cancer.
abstract: BACKGROUND
  Muscle-invasive bladder cancer (MIBC) can be cured by radical radiotherapy (RT). We previously found tumour MRE11 expression to be predictive of survival following RT in MIBC, and this was independently validated in a separate institute. Here, we investigated germline MRE11A variants as possible predictors of RT outcomes in MIBC, using next-generation sequencing (NGS).
  
  
  METHODS
  The MRE11A gene was amplified in germline DNA from 186 prospectively recruited MIBC patients treated with RT and sequenced using bar-coded multiplexed NGS. Germline variants were analysed for associations with cancer-specific survival (CSS). For validation as a prognostic or predictive marker, rs1805363 was then genotyped in a cystectomy-treated MIBC cohort of 256 individuals. MRE11A mRNA isoform expression was measured in bladder cancer cell lines and primary tumour samples.
  
  
  RESULTS
  Carriage of at least one of six (five novel) rare variants was associated with the worse RT outcome (hazard ratio [HR] 4.04, 95% confidence interval [95% CI] 1.42-11.51, P = 0.009). The single-nucleotide polymorphism (SNP), rs1805363 (minor allele frequency 11%), was also associated with worse CSS (per-allele HR 2.10, 95% CI 1.34-3.28, Ptrend = 0.001) following RT in MIBC, with a gene-dosage effect observed, but no effect seen on CSS in the cystectomy cohort (Ptrend = 0.89). Furthermore, rs1805363 influenced relative MRE11A isoform expression, with increased isoform 2 expression with carriage of the rs1805363 minor A allele.
  
  
  CONCLUSIONS
  Germline MRE11A SNP rs1805363 was predictive of RT, but not of cystectomy outcome in MIBC. If successfully validated in an independent RT-treated cohort, this SNP could be a useful clinical tool for selecting patients for bladder-conserving treatment.
authors.affiliation: Section of Epidemiology and Biostatistics, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: M T W
authors.initials: MTW
authors.lastname: Teo
authors.affiliation: Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Dyrskjøt
authors.affiliation: Section of Epidemiology and Biostatistics, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: J
authors.initials: J
authors.lastname: Nsengimana
authors.affiliation: Department of Oncology, Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford.
authors.forename: C
authors.initials: C
authors.lastname: Buchwald
authors.affiliation: Section of Epidemiology and Biostatistics, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: H
authors.initials: H
authors.lastname: Snowden
authors.affiliation: Genomics Facility, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: J
authors.initials: J
authors.lastname: Morgan
authors.affiliation: Department of Urology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: J B
authors.initials: JB
authors.lastname: Jensen
authors.affiliation: Section of Experimental Oncology, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Knowles
authors.affiliation: Genomics Facility, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: G
authors.initials: G
authors.lastname: Taylor
authors.affiliation: Section of Epidemiology and Biostatistics, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: J H
authors.initials: JH
authors.lastname: Barrett
authors.affiliation: Department of Urology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Borre
authors.affiliation: Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: T F
authors.initials: TF
authors.lastname: Ørntoft
authors.affiliation: Section of Epidemiology and Biostatistics, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.
authors.forename: D T
authors.initials: DT
authors.lastname: Bishop
authors.affiliation: Department of Oncology, Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford. Electronic address: anne.kiltie@oncology.ox.ac.uk.
authors.forename: A E
authors.initials: AE
authors.lastname: Kiltie
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D005260:Female; D018095:Germ-Line Mutation; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D000076228:MRE11 Homologue Protein; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D016896:Treatment Outcome; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C121766:MRE11 protein, human; D000076228:MRE11 Homologue Protein
keywords: MRE11A; biomarkers; bladder cancer; cystectomy; next-generation sequencing; radiotherapy