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Effect of soybean on breast cancer according to receptor status: A case–control study in Japan
Author(s) -
Suzuki Takeshi,
Matsuo Keitaro,
Tsunoda Nobuyuki,
Hirose Kaoru,
Hiraki Akio,
Kawase Takakazu,
Yamashita Toshinari,
Iwata Hiroji,
Tanaka Hideo,
Tajima Kazuo
Publication year - 2008
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.23644
Subject(s) - breast cancer , medicine , odds ratio , estrogen receptor , oncology , case control study , confidence interval , confounding , risk factor , cancer , gynecology , physiology
The possible association of high soy food consumption with low incidence of breast cancer in Asian countries has been widely investigated, but findings from epidemiologic studies have been inconsistent. Breast cancers defined by receptor status, estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) may have distinct etiologic factors. Here, we conducted a case–control study to clarify associations between intake of soybean products and breast cancer risk according to receptor status. A total of 678 breast cancer cases and 3,390 age‐ and menopausal status‐matched noncancer controls were included. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using conditional logistic models adjusted for potential confounders. On analysis according to receptor status, we observed a significantly reduced risk of ER‐positive (ER+) (top tertile OR = 0.74; 95% CI, 0.58–0.94; trend p = 0.01) and HER2‐negative (HER2−) tumors (top tertile OR = 0.78; 95% CI, 0.61–0.99; trend p = 0.04). Further, when the 3 receptors were jointly examined, a reduced risk was observed only in patients with ER+/PR+/HER2− tumor (top tertile OR = 0.73; 95% CI, 0.54–0.97; trend p = 0.03). These findings indicate that the protective effect of soy against breast cancer risk differs by receptor status. © 2008 Wiley‐Liss, Inc.