Oral contraceptive use and other risk factors in relation to HER-2/neu overexpression in breast cancer among young women.
This study was undertaken to explore whether the incidence of breast tumors that overexpress HER-2/neu protein product (HER-2/neu+) is more strongly associated with oral contraceptives (OCs) and other factors than is the incidence of tumors that do not (HER-2/neu-). In a population-based sample of women <45 years, 42.9% (159 of 371) of in situ and invasive breast cancer cases were HER-2/neu+ as assessed by immunohistochemistry in archived tissue. Polytomous logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for HER-2/neu+ and HER-2/neu-breast cancer, as compared with 462 population-based controls, in relation to OCs and other factors. The ratio of the ORs (HER-2/neu+ versus HER-2/neu-tumors) was used as an indicator of heterogeneity in risk. There was little heterogeneity in risk for OC use of 6 months or more by HER-2/neu status (age-adjusted ratio of ORs, 1.29; 95% CI, 0.83-2.00). Among early pill users (< or =18 years of age) heterogeneity was apparent (2.39; 95% CI, 1.08-5.30), which was attenuated in a multivariate model (1.99; 95% CI, 0.87-4.54); among cases with estrogen receptor-negative tumors, heterogeneity increased to 5-fold. For other risk factors, there was no marked heterogeneity between + and - tumors for HER-2/neu. In summary, the incidence of breast cancer among younger women in relation to OC use at an early age varied with HER-2/neu status, with the odds ratio for +tumors twice that for -tumors.
Gammon
M D
MD
Columbia University, Joseph L. Mailman School of Public Health, Division of Epidemiology, New York, New York 10032, USA.
Hibshoosh
H
H
Terry
M B
MB
Bose
S
S
Schoenberg
J B
JB
Brinton
L A
LA
Bernstein
J L
JL
Thompson
W D
WD
D000328:Adult; D017677:Age Distribution; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000009:adverse effects*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D009376:Neoplasms, Hormone-Dependent / Q000453:epidemiology* / Q000209:etiology*; D009515:New Jersey / Q000453:epidemiology; D016017:Odds Ratio; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012307:Risk Factors
D003276:Contraceptives, Oral; D018719:Erb-b2 Receptor Tyrosine Kinases