Dietary lignans and postmenopausal breast cancer risk by oestrogen receptor status: a prospective cohort study of Swedish women
Dietary lignans and postmenopausal breast cancer risk by oestrogen receptor status: a prospective cohort study of Swedish women
Year: 2008
Authors: Suzuki, R. Rylander-Rudqvist, T. Saji, S. Bergkvist, L. Adlercreutz, H. Wolk, A.
Publication Name: British Journal of Cancer
Publication Details: Volume 98; Pages 636 – 640.
Abstract:
Among the 51,823 postmenopausal women in the Swedish Mammography Cohort, we investigated breast cancer risk in relation to the FFQ-based estimated lignan intake by oestrogen receptor (ER) and progesterone receptor (PR) subtypes. A significant 17% risk reduction for breast cancer overall in the high lignan quartile was observed, especially among PMH user (P for interaction < 0.010), but no heterogeneity across ER/PR subtypes. (Authors abstract)
Plant lignans are metabolised to mammalian lignans (e.g. enterolactone (ENL)) by the intestinal microflora and have preventive action of lignans against breast cancer. Hormone-dependent and other mechanisms have been suggested. Research has evaluated the relationship among postmenopausal women. Of these, only four considered oestrogen and progesterone receptor status of tumours (ER/PR). This study investigated estimated lignan intake by oestrogen receptor (ER) and progesterone receptor (PR) subtypes in a large population-based cohort study with stratification by family history of breast cancer, level of alcohol intake, body mass index, and use of postmenopausal hormone (PMH). A significant inverse association between lignan intake and overall breast cancer risk, especially among PMH users was observed. There was no evidence of heterogeneity across ER/PR tumours. The estimated lignan intake was correlated with cereal fibre and after adjusting for specific fibres, the association among PMH users was still significant. The possible biological mechanism is not clear. In vitro studies have shown that lignan ENL in the presence of oestrogens suppresses the oestrogen-induced proliferation in MCF-7 breast cancer cell. The study shows a lack of association among overweight women which may be due to the relatively high circulating oestrogen levels from PMH use having a stronger effect than the endogenous oestrogens formed in peripheral tissues. Lignan estimates were not highly correlated with plasma ENL. Further studies need to be undertaken with circulating level of oestrogens taken into consideration. (Editors comments)
Plant lignans are metabolised to mammalian lignans (e.g. enterolactone (ENL)) by the intestinal microflora and have preventive action of lignans against breast cancer. Hormone-dependent and other mechanisms have been suggested. Research has evaluated the relationship among postmenopausal women. Of these, only four considered oestrogen and progesterone receptor status of tumours (ER/PR). This study investigated estimated lignan intake by oestrogen receptor (ER) and progesterone receptor (PR) subtypes in a large population-based cohort study with stratification by family history of breast cancer, level of alcohol intake, body mass index, and use of postmenopausal hormone (PMH). A significant inverse association between lignan intake and overall breast cancer risk, especially among PMH users was observed. There was no evidence of heterogeneity across ER/PR tumours. The estimated lignan intake was correlated with cereal fibre and after adjusting for specific fibres, the association among PMH users was still significant. The possible biological mechanism is not clear. In vitro studies have shown that lignan ENL in the presence of oestrogens suppresses the oestrogen-induced proliferation in MCF-7 breast cancer cell. The study shows a lack of association among overweight women which may be due to the relatively high circulating oestrogen levels from PMH use having a stronger effect than the endogenous oestrogens formed in peripheral tissues. Lignan estimates were not highly correlated with plasma ENL. Further studies need to be undertaken with circulating level of oestrogens taken into consideration. (Editors comments)
