Estrogenic activity and risk of invasive breast cancer among postmenopausal women in the Nurses' Health Study

Excess body weight and postmenopausal breast cancer: Emerging molecular mechanisms and perspectives

Postmenopausal, obese women have a significantly higher risk of developing estrogen receptor-positive (ER+) breast tumors, that are resistant to therapies and are associated with higher recurrence and death rates. The global prevalence of overweight/obese women has reached alarming proportions and with postmenopausal ER+ breast carcinoma (BC) having the highest incidence among the three obesity-related cancers in females (i.e., breast, endometrial and ovarian), this is of significant concern. Elucidation of the precise molecular mechanisms underlying the pro-cancerous action of obesity in ER+BC is therefore critical for disease prevention and novel treatment initiatives. Interestingly, accumulating data has shown opposing relationships between obesity and cancer in either pre- or post-menopausal women. Excess body weight is associated with an increased risk of breast cancer in postmenopausal women and a decreased risk in pre-menopausal women. Moreover, excess adiposity during early life appears to be protective against postmenopausal breast cancer, including both ER+ and ER negative BC subtypes. Overall, estrogen-dependent mechanisms have been implicated as the main driving force in obesity-related breast tumorigenesis. In the present review we discuss the epidemiologic and mechanistic aspects of association between obesity and breast tumors after menopause, mainly in the context of hormone dependency. Molecular and cellular events underlying this association present as potential avenues for both therapeutic intervention as well as the prevention of BC-promoting processes linked to excess adiposity, which is proving to be vital in an increasingly obese global population.

Cancer Prevention Prioritized at AACR Annual Meeting and a New Working Group

Scientific advances in the late 19th century set the stage for progress in understanding and treating cancer, a disease that was previously considered almost hopeless. One hundred years later, cancer prevention is becoming an increasingly important focus for oncology research. New tools and ideas bring to the field some extremely promising molecular, organizational, social, and political approaches, which were a focus of the American Association for Cancer Research 2022 Annual Meeting and of the newly launched AACR Cancer Prevention Working Group (CPWG). We are moving toward precision prevention, better tools for early detection and for risk assessment, the use of a Precancer Atlas, unveiling of new biomarkers. Besides improving lifestyle, by avoiding risk factors such as tobacco use, excessive UV exposure, infectious agents, as well as poor dietary habits, lack of exercise, overweight, and obesity, many other factors can impact cancer risk, which is a warning to consider a multifaceted molecular but also social approach. Gender, ethnicity, geographic, and economic lines are associated with disparities in prevention, which we want to overcome. Here we summarize some challenges and priorities in cancer prevention emerging from the work of AACR and CPWG.