The Association between Dietary Patterns and Breast Cancer Pathobiological Factors Progesterone Receptor (PR) and Estrogen Receptors (ER): New Findings from Iranian Case-Control Study.

Background: Breast cancer (BrCa) is the most frequently diagnosed cancer among females and second cancer after lung cancer in many societies. Ignoring the phenotypes of the BrCa can affect the interpretation of the association between diet and BrCa. The aim of this study was to determine the association between dietary patterns and estrogen receptor (ER), and progesterone receptor (PR) status in women with BrCa. Methods: This study includes 150 cases of BrCa. Controls were 150 healthy adults, frequency matching based on age. The individual information, food frequency questionnaire, and physical activity were completed while interviews. Information about the pathologic factors obtained from patients' files. Factor analysis method used to determine the dietary patterns; logistic regression used to measure the odds ratios. Results: Getting upper median intake of unhealthy diet had a strong association with BrCa-positive ER and positive PR (OR: 4.98, 95% CI: 2.65-9.34 and OR: 4.99, 95% CI: 2.56-9.75, respectively) compared to under median intake of unhealthy diet. In addition, the protective effect of the healthy diet was stronger on BrCa-negative ER, negative PR (OR: 0.11, 95% CI: 0.04-0.34 and OR: 0.10, 95% CI: 0.03-0.25, respectively). Conclusion: The protective effect of a healthy dietary pattern was stronger on BrCa negative ER and negative PR. The unhealthy dietary pattern had a strong association with BrCa positive ER and positive PR.