title: Breast cancer in neurofibromatosis type 1: overrepresentation of unfavourable prognostic factors.
abstract: BACKGROUND
  An increased breast cancer incidence and poor survival have been reported for women with neurofibromatosis 1 (NF1). To explain the poor survival, we aimed to link the histopathology and clinical characteristics of NF1-associated breast cancers.
  
  
  METHODS
  The Finnish Cancer Registry and the Finnish NF Registry were cross-referenced to identify the NF1 patients with breast cancer. Archival NF1 breast cancer specimens were retrieved for histopathological typing and compared with matched controls.
  
  
  RESULTS
  A total of 32 breast cancers were diagnosed in 1404 NF1 patients during the follow-up. Women with NF1 had an estimated lifetime risk of 18.0% for breast cancer, and this is nearly two-fold compared with that of the general Finnish female population (9.74%). The 26 successfully retrieved archival NF1 breast tumours were more often associated with unfavourable prognostic factors, such as oestrogen and progesterone receptor negativity and HER2 amplification. However, survival was worse in the NF1 group (P=0.053) even when compared with the control group matched for age, diagnosis year, gender and oestrogen receptor status. Scrutiny of The Cancer Genome Atlas data set showed that NF1 mutations and deletions were associated with similar characteristics in the breast cancers of the general population.
  
  
  CONCLUSIONS
  These results emphasise the role of the NF1 gene in the pathogenesis of breast cancer and a need for active follow-up for breast cancer in women with NF1.
authors.affiliation: Department of Cell Biology and Anatomy, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.
authors.forename: Elina
authors.initials: E
authors.lastname: Uusitalo
authors.affiliation: Department of Cell Biology and Anatomy, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.
authors.forename: Roope A
authors.initials: RA
authors.lastname: Kallionpää
authors.affiliation: Auria Biobank, University of Turku and Turku University Hospital, Kiinamyllynkatu 8, 20520 Turku, Finland.
authors.forename: Samu
authors.initials: S
authors.lastname: Kurki
authors.affiliation: Finnish Cancer Registry-Institute for Statistical and Epidemiological Cancer Research, Unioninkatu 22, 00130 Helsinki, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Rantanen
authors.affiliation: Finnish Cancer Registry-Institute for Statistical and Epidemiological Cancer Research, Unioninkatu 22, 00130 Helsinki, Finland.|Department of Public Health, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Janne
authors.initials: J
authors.lastname: Pitkäniemi
authors.affiliation: Department of Pathology, University of Turku and Turku University Hospital, Kiinamyllynkatu 10, 20520 Turku, Finland.
authors.forename: Pauliina
authors.initials: P
authors.lastname: Kronqvist
authors.affiliation: Department of Cell Biology and Anatomy, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.
authors.forename: Pirkko
authors.initials: P
authors.lastname: Härkönen
authors.affiliation: Department of Oncology and Radiotherapy, Turku University Hospital, PB 52, 20521 Turku, Finland.
authors.forename: Riikka
authors.initials: R
authors.lastname: Huovinen
authors.affiliation: Auria Biobank, University of Turku and Turku University Hospital, Kiinamyllynkatu 8, 20520 Turku, Finland.|Department of Pathology, University of Turku and Turku University Hospital, Kiinamyllynkatu 10, 20520 Turku, Finland.|Department of Pathology, University of Helsinki and Helsinki University Hospital, PB 67, 00014 Helsinki, Finland.
authors.forename: Olli
authors.initials: O
authors.lastname: Carpen
authors.affiliation: Department of Clinical Genetics, HUSLAB, Helsinki University Central Hospital, PB 160, 00029 Helsinki, Finland.|Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Pöyhönen
authors.affiliation: Department of Dermatology, University of Turku and Turku University Hospital, PB 52, 20521 Turku, Finland.
authors.forename: Sirkku
authors.initials: S
authors.lastname: Peltonen
authors.affiliation: Department of Cell Biology and Anatomy, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.|Department of Cell Biology and Anatomy, University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Peltonen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics; D018567:Breast Neoplasms, Male / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D016022:Case-Control Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009456:Neurofibromatosis 1 / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics; D011379:Prognosis; D012042:Registries; D012307:Risk Factors