Carcinogenesis Advance Access published online on August 18, 2008
Carcinogenesis, doi:10.1093/carcin/bgn196
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Plant foods and estrogen receptor 
and β defined breast cancer: observations from the Malmö Diet and Cancer cohort
1 Department of Clinical Sciences in Malmö, Lund University, Malmö, Sweden
2 Center of Molecular Pathology, Department of Laboratory Medicine, Lund University, Malmö, Sweden
3 Department of Clinical Sciences in Lund, Lund University, Lund, Sweden
Correspondence to: Emily Sonestedt, Lund University, Department of Clinical Sciences in Malmö, Research group in Nutrition Epidemiology, UMAS, CRC Entrance 72, Building 60 Floor 13, SE-205 02 Malmö, Sweden., Phone: +46 40 39 13 24, Fax: +46 40 39 13 22, E-mail: Emily.Sonestedt{at}med.lu.se
The associations between plant foods and breast cancer incidence are inconsistent. The objective of this study was to examine prospectively the association between dietary fibre, plant foods and breast cancer, especially the association between plant food intake and estrogen receptor (ER) 
and β defined breast cancer. Among women without prevalent cancer from the population-based prospective Malmö Diet and Cancer cohort (n = 15,773, 46-75 years at baseline), 544 women were diagnosed with incident invasive breast cancer during a mean follow-up of 10.3 years. Information on dietary habits was collected by a modified diet history method. ER status of the tumours was determined by immunohistochemistry using tissue microarray. Cox proportional hazards regression estimated hazard ratios (HR) and 95% confidence intervals (CI) of breast cancer associated with fibre and 11 plant food groups. High-fibre bread was significantly associated with a decreased breast cancer incidence (HR, 0.75, 95 % CI, 0.57-0.98, for highest compared to lowest quintile). The other plant food groups were not significantly associated with breast cancer incidence. There was a tendency for a negative association for high-fibre bread among ER (+) breast cancer (p for trend = 0.06) and ERβ (+) breast cancer (p for trend = 0.06). Fried potatoes were statistically significantly associated with increased risk of ERβ (-) breast cancer (p = 0.01). This study suggests that different plant foods may be differently associated with breast cancer, with fibre-rich bread showing an inverse association. We did not observe strong evidence for differences in incidence according to the ER and β status of breast cancer.
Key Words: prospective study • breast cancer • estrogen receptor • estrogen receptor β • plant foods
Received March 17, 2008; revised August 12, 2008; accepted August 13, 2008.