title: Mutation profile of differentiated thyroid tumours in an Australian urban population.
abstract: BACKGROUND
  The majority of differentiated thyroid cancers are characterised by one of several point mutations or gene rearrangements. Limited data are available on the prevalence and clinical correlations of these mutations in the Australian population.
  
  
  OBJECTIVE
  The aim of the present study was to characterise the mutation profile of differentiated thyroid tumours in the local population.
  
  
  METHODS
  The study involved 148 patients with differentiated thyroid cancer. The following tumours were examined: 109 papillary carcinomas (PTC), 27 follicular carcinomas (FC) and 12 Hurthle cell carcinomas (HCC). Polymerase chain reaction (PCR) was performed for BRAF and RAS mutations (RNA and DNA) as well as for RET/PTC rearrangements and PAX8-PPARγ translocations (RNA). Clinicopathological parameters and outcome data were analysed according to BRAFV600E status in PTC and RAS mutation status in FC.
  
  
  RESULTS
  BRAFV600E was identified in 74/109 (68%) PTC. BRAFV600E was not significantly correlated with clinicopathological features of aggressive disease. At a median follow up of 48 months, there was no significant difference between BRAFV600E and wild-type BRAF PTC with respect to the rates of nodal recurrence, distant metastases or disease-specific death. In FC, RAS mutations (five NRAS and three HRAS) were present in 8/27 (30%) tumours. RAS mutation was significantly associated with widely invasive histology (P = 0.01) and distant metastases (P = 0.01) on follow up.
  
  
  CONCLUSIONS
  In the present study, BRAF mutation was not associated with negative prognostic indicators or adverse outcomes in PTC. RAS mutation was positively correlated with aggressive features in FC suggesting potential prognostic utility, although confirmation is required from larger studies.
authors.affiliation: Centre for Endocrinology and Metabolism, MIMR-PHI Institute of Medical Research, Melbourne, Victoria, Australia; Eastern Clinical School and Eastern Clinical Research Unit, Monash University, Box Hill Hospital, Melbourne, Victoria, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Mond
authors.forename: M
authors.initials: M
authors.lastname: Alexiadis
authors.forename: P J
authors.initials: PJ
authors.lastname: Fuller
authors.forename: C
authors.initials: C
authors.lastname: Gilfillan
mesh_terms: D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011379:Prognosis; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000601:surgery; D013965:Thyroidectomy; D014505:Urban Population; D014739:Victoria / Q000453:epidemiology
chemical_list: D004273:DNA, Neoplasm; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf
keywords: BRAF; RAS; mutation; thyroid cancer