Abstract | BACKGROUND: METHODS: We considered plasma bioactive prolactin levels measured by the Nb2 lymphoma cell bioassay, which is sensitive to the somatolactogenic activity of prolactin and growth hormone, within a nested case-control study of invasive breast cancer in the Nurses' Health Studies (NHS/NHSII). We also considered associations with breast cancer risk factors. RESULTS: We had bioassay measures on 1,329 cases and 1,329 controls. Bioassay levels were inversely associated with parity (4+ vs. 0 children = -18%, P = 0.01), body mass index (30+ vs. <22 kg/m(2) = -16%, P < 0.01), and age at menopause (53+ vs. 48 years = -18%, P = 0.03) and positively with family history of breast cancer (yes vs. no = 14%, P < 0.01). The relative risk (RR) comparing the top versus bottom quartile of bioassay levels was 1.19 [95% confidence intervals (CI), 0.94-1.51; Ptrend = 0.18]. The association was suggestively stronger for postmenopausal (RR = 1.36; 95% CI, 0.93-1.98; Ptrend = 0.12) versus premenopausal women (RR = 0.99; 95% CI, 0.71-1.37; Ptrend = 0.71). There was an association for cases diagnosed <4 years after blood draw (RR = 2.66; 95% CI, 1.45-4.89; Ptrend < 0.01), but not for cases diagnosed later. We did not observe differential associations by estrogen receptor status or other tumor characteristics. CONCLUSIONS: Our results show similar associations for prolactin levels measured by bioassay and by immunoassay with both breast cancer risk factors and risk. IMPACT: Future work examining risk prediction model of breast cancer can use the immunoassay to accurately characterize risk.
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Authors | Shelley S Tworoger, Megan S Rice, Bernard A Rosner, Yvonne B Feeney, Charles V Clevenger, Susan E Hankinson |
Journal | Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology
(Cancer Epidemiol Biomarkers Prev)
Vol. 24
Issue 1
Pg. 73-80
(Jan 2015)
ISSN: 1538-7755 [Electronic] United States |
PMID | 25315962
(Publication Type: Journal Article, Research Support, N.I.H., Extramural)
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Copyright | ©2014 American Association for Cancer Research. |
Chemical References |
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Topics |
- Breast Neoplasms
(metabolism)
- Case-Control Studies
- Female
- Humans
- Pilot Projects
- Prolactin
(blood)
- Prospective Studies
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