title: Polygenic susceptibility to testicular cancer: implications for personalised health care.
abstract: BACKGROUND
  The increasing incidence of testicular germ cell tumour (TGCT) combined with its strong heritable basis suggests that stratified screening for the early detection of TGCT may be clinically useful. We modelled the efficiency of such a personalised screening approach, based on genetic risk profiling in combination with other diagnostic tools.
  
  
  METHODS
  We compared the number of cases potentially detectable in the population under a number of screening models. The polygenic risk scoring (PRS) model was assumed to have a log-normal relative risk distribution across the 19 currently known TGCT susceptibility variants. The diagnostic performance of testicular biopsy and non-invasive semen analysis was also assessed, within a simulated combined screening programme.
  
  
  RESULTS
  The area under the curve for the TGCT PRS model was 0.72 with individuals in the top 1% of the PRS having a nine-fold increased TGCT risk compared with the population median. Results from population-screening simulations only achieved a maximal positive predictive value (PPV) of 60%, highlighting broader clinical factors that challenge such strategies, not least the rare nature of TGCT. In terms of future improvements, heritability estimates suggest that a significant number of additional genetic risk factors for TGCT remain to be discovered, identification of which would potentially yield improvement of the PPV to 80-90%.
  
  
  CONCLUSIONS
  While personalised screening models may offer enhanced TGCT risk discrimination, presently the case for population-level testing is not compelling. However, future advances, such as more routine generation of whole genome data is likely to alter the landscape. More targeted screening programs may plausibly then offer clinical benefit, particularly given the significant survivorship issues associated with the successful treatment of TGCT.
authors.affiliation: Division of Genetics and Epidemiology, The Institute of Cancer Research, London SW3 6JB, UK.
authors.forename: Kevin
authors.initials: K
authors.lastname: Litchfield
authors.affiliation: Division of Genetics and Epidemiology, The Institute of Cancer Research, London SW3 6JB, UK.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Mitchell
authors.affiliation: Division of Molecular Pathology, The Institute of Cancer Research, London SW3 6JB, UK.|Division of Cancer Therapeutics, The Institute of Cancer Research, London SW3 6JB, UK.
authors.forename: Janet
authors.initials: J
authors.lastname: Shipley
authors.affiliation: Academic Radiotherapy Unit, The Institute of Cancer Research, London SW3 6JB, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Huddart
authors.affiliation: Department of Growth and Reproduction, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors.forename: Ewa
authors.initials: E
authors.lastname: Rajpert-De Meyts
authors.affiliation: Department of Growth and Reproduction, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors.forename: Niels E
authors.initials: NE
authors.lastname: Skakkebæk
authors.affiliation: Division of Genetics and Epidemiology, The Institute of Cancer Research, London SW3 6JB, UK.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Houlston
authors.affiliation: Division of Genetics and Epidemiology, The Institute of Cancer Research, London SW3 6JB, UK.|William Harvey Research Institute, Queen Mary University, London EC1M 6BQ, UK.
authors.forename: Clare
authors.initials: C
authors.lastname: Turnbull
mesh_terms: D001706:Biopsy; D055088:Early Detection of Cancer / Q000379:methods*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008957:Models, Genetic; D020412:Multifactorial Inheritance; D009373:Neoplasms, Germ Cell and Embryonal / Q000175:diagnosis / Q000235:genetics*; D066230:Patient-Specific Modeling; D057285:Precision Medicine / Q000379:methods*; D011237:Predictive Value of Tests; D055101:Semen Analysis / Q000379:methods; D013736:Testicular Neoplasms / Q000175:diagnosis / Q000235:genetics*