title: Risk of breast cancer according to the status of HER-2/neu oncogene amplification.
abstract: We examined risk factors for breast cancer after subdividing cases based on the presence of HER-2/neu oncogene amplification in their tumors. Data were from the Carolina Breast Cancer Study, a population-based, case-control study of 577 invasive breast cancer patients, diagnosed during 1993-1996 and ages 20-74 years, and 790 controls frequency-matched on race and age. Information on breast cancer risk factors was obtained from structured personal interviews. About 20% of paraffin-embedded tissues from the breast cancers of cases were identified as positive for HER-2/neu amplification (HER-2/neu+) by differential PCR. Early age at menarche, higher waist:hip ratio, and family history of breast or ovarian cancer were associated with elevated odds ratios (ORs) for both HER-2/neu+ and HER-2/neu- breast cancers. Breastfeeding for at least 1 year was inversely associated with HER-2/neu+ breast cancer [OR, 0.3; 95% confidence interval (CI), 0.1-0.7] more so than HER-2/neu- breast cancer (OR, 0.8; 95% CI, 0.5-1.2). Most of the remaining risk factors had ORs around 1.0 for both HER-2/neu+ and HER-2/neu- breast cancers, although a few exhibited possible associations with one disease subtype in analyses stratified by menopausal status. These study results suggest that most recognized breast cancer risk factors do not operate through HER-2/neu amplification in breast carcinogenesis. Differential effects of long-term breastfeeding by HER-2/neu amplification status have been observed in earlier studies and are provocative; however, the direction and magnitude of the associations have not been consistent.
authors.affiliation: Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill 27599, USA.
authors.forename: W Y
authors.initials: WY
authors.lastname: Huang
authors.forename: B
authors.initials: B
authors.lastname: Newman
authors.forename: R C
authors.initials: RC
authors.lastname: Millikan
authors.forename: K
authors.initials: K
authors.lastname: Conway
authors.forename: B S
authors.initials: BS
authors.lastname: Hulka
authors.forename: M J
authors.initials: MJ
authors.lastname: Schell
authors.forename: E T
authors.initials: ET
authors.lastname: Liu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001824:Body Constitution; D001942:Breast Feeding; D001943:Breast Neoplasms / Q000209:etiology* / Q000235:genetics / Q000473:pathology; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D005784:Gene Amplification / Q000235:genetics*; D018734:Genes, erbB-2 / Q000235:genetics*; D006801:Humans; D007407:Interviews as Topic; D008572:Menarche; D008593:Menopause; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D016017:Odds Ratio; D010051:Ovarian Neoplasms / Q000235:genetics; D016612:Paraffin Embedding; D011159:Population Surveillance; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D012307:Risk Factors
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases