Plasma Folate Concentrations Are Positively Associated with Risk of Estrogen Receptor {beta} Negative Breast Cancer in a Swedish Nested Case Control Study.
Folate's role in breast cancer development is controversial. Not only estrogen receptor (ER) alpha status, but also ERbeta status of tumors may have confounded results from previous epidemiological studies. We aimed to examine associations between plasma folate concentration and postmenopausal breast cancer defined by ER status. This nested case-control study, within the Malmö diet and cancer coho