AUTHOR=Li Liangliang , Li Shuo , Qin Shidong , Gao Yu , Wang Chao , Du Jinghang , Zhang Nannan , Chen Yanbo , Han Zhen , Yu Yue , Wang Fan , Zhao Yashuang 

TITLE=Diet, Sports, and Psychological Stress as Modulators of Breast Cancer Risk: Focus on OPRM1 Methylation

JOURNAL=Frontiers in Nutrition

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2021.747964

DOI=10.3389/fnut.2021.747964

ISSN=2296-861X

ABSTRACT=<p><bold>Background:</bold> DNA methylation is influenced by environmental factors and contributes to adverse modification of cancer risk and clinicopathological features.</p><p><bold>Methods:</bold> A case-control study (402 newly diagnosed cases, 470 controls) was conducted to evaluate the effect of environmental factors and <italic>OPRM1</italic> methylation in peripheral blood leukocyte (PBL) DNA on the risk of breast cancer. A case-only study (373 cases) was designed to evaluate the effects of environmental factors on <italic>OPRM1</italic> methylation in tumor tissue and the relationship of methylation with clinicopathological features.</p><p><bold>Results:</bold> We found a significant association between hypermethylation of <italic>OPRM1</italic> and the risk of breast cancer (OR = 1.914, 95%CI = 1.357–2.777). <italic>OPRM1</italic> hypermethylation in PBL DNA combined with low intake of vegetable, garlic, soybean, poultry, and milk; high pork intake; less regular sports and a high psychological stress index significantly increased the risk of breast cancer. Soybean intake (OR = 0.425, 95%CI: 0.231–0.781) and regular sports (OR = 0.624, 95%CI: 0.399–0.976) were associated with <italic>OPRM1</italic> hypermethylation in tumor DNA. <italic>OPRM1</italic> hypermethylation in tumor tissue was correlated with estrogen receptor (ER) (OR = 1.945, 95%CI: 1.262–2.996) and progesterone receptor (PR) (OR = 1.611, 95%CI: 1.069–2.427) negative status; in addition, <italic>OPRM1</italic> hypermethylation in PBL DNA was associated with human epidermal growth factor receptor 2 (HER-2) negative status (OR = 3.673, 95%CI: 1.411–9.564).</p><p><bold>Conclusion:</bold> A healthy diet, psychosocial adaptability, and regular sports are very beneficial for breast cancer prevention and progress, especially for <italic>OPRM1</italic> hypermethylation carriers. Personalized treatment considering the correlation between <italic>OPRM1</italic> hypermethylation and ER and PR status may provide a novel benefit for breast cancer patients.</p>