title: Circulating gamma-glutamyl transferase and development of specific breast cancer subtypes: findings from the Apolipoprotein Mortality Risk (AMORIS) cohort.
abstract: Different etiological pathways may precede development of specific breast cancer subtypes and impact prevention or treatment strategies. We investigated the association between gamma-glutamyl transferase (GGT) and development of specific breast cancer subtypes based on oestrogen receptor (ER), progesterone receptor (PR) and HER2 status.
  
  
  
  We included 231,283 cancer-free women in a Swedish cohort. Associations between GGT and breast cancer subtypes were investigated with nested case-control and case-case analyses. We used logistic regression models to assess serum GGT in relation to breast cancer subtype, based on individual and combined receptor status.
  
  
  
  Positive associations were found between serum GGT and development of ER+, ER- and PR+ breast cancers compared to controls (odds ratio (OR) 1.14 (95% confidence interval (CI) 1.08-1.19), 1.11 (1.01-1.23) and 1.18 (1.12-1.24), respectively) and of ER+/PR+ tumours. We found inverse associations between GGT levels and PR- breast cancers compared to PR+ (OR 0.87 (0.80-0.95)), between ER+/PR- tumours compared to ER+/PR+ tumours and between ER-/PR-/HER+ compared to ER+/HER2 or PR+/HER2 tumours (OR 0.55 (95% CI 0.34-0.90).
  
  
  
  The observed associations between pre-diagnostic serum GGT and different breast cancer subtypes may indicate distinct underlying pathways and require further investigations to tease out their clinical implications.
authors.affiliation: Division of Cancer Studies, Cancer Epidemiology Group, King's College London, Faculty of Life Sciences & Medicine, Guy's Hospital, 3rd Floor, Bermondsey Wing, London, SE1 9RT, UK.
authors.forename: Lydia
authors.initials: L
authors.lastname: Shackshaft
authors.affiliation: Division of Cancer Studies, Cancer Epidemiology Group, King's College London, Faculty of Life Sciences & Medicine, Guy's Hospital, 3rd Floor, Bermondsey Wing, London, SE1 9RT, UK.|Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mieke
authors.initials: M
authors.lastname: Van Hemelrijck
authors.affiliation: Division of Cancer Studies, Cancer Epidemiology Group, King's College London, Faculty of Life Sciences & Medicine, Guy's Hospital, 3rd Floor, Bermondsey Wing, London, SE1 9RT, UK.|Regional Cancer Centre, Uppsala, Sweden.
authors.forename: Hans
authors.initials: H
authors.lastname: Garmo
authors.affiliation: Unit of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Malmström
authors.affiliation: Regional Cancer Centre, Uppsala, Sweden.|Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Lambe
authors.affiliation: AstraZeneca R&D, Mölndal, Sweden.|Unit of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Niklas
authors.initials: N
authors.lastname: Hammar
authors.affiliation: Unit of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Walldius
authors.affiliation: Department of Medicine, Clinical Epidemiological Unit, Karolinska Institutet and CALAB Research, Stockholm, Sweden.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Jungner
authors.affiliation: Division of Cancer Studies, Cancer Epidemiology Group, King's College London, Faculty of Life Sciences & Medicine, Guy's Hospital, 3rd Floor, Bermondsey Wing, London, SE1 9RT, UK. wahyu.wulaningsih@kcl.ac.uk.|MRC Unit for Lifelong Health and Ageing at University College London, London, UK. wahyu.wulaningsih@kcl.ac.uk.
authors.forename: Wahyu
authors.identifier: 0000-0002-3822-1648
authors.initials: W
authors.lastname: Wulaningsih
mesh_terms: D000328:Adult; D000368:Aged; D001053:Apolipoproteins / Q000378:metabolism; D015415:Biomarkers; D001943:Breast Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology / Q000378:metabolism; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011159:Population Surveillance; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D013548:Sweden / Q000453:epidemiology; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D001053:Apolipoproteins; D015415:Biomarkers; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D005723:gamma-Glutamyltransferase
keywords: Breast cancer; GGT; Glucose; Prospective study; Triglycerides