What are the causes of breast cancer
Pro Research Analysisby 
Searched over 200M research papers
Consensus Meter
Causes of Breast Cancer: A Comprehensive Overview
Breast cancer is a multifaceted disease with a variety of contributing factors. Understanding these causes is crucial for prevention, early detection, and effective treatment. This article synthesizes findings from multiple research studies to provide a clear picture of the primary causes of breast cancer.
Demographic and Reproductive Factors
Age and Gender
Breast cancer predominantly affects women, and the risk increases with age. The majority of cases occur in women over the age of 50 .
Reproductive History
Reproductive factors play a significant role in breast cancer risk. Early menarche (the onset of menstruation) and late menopause are associated with higher risk due to prolonged exposure to estrogen . Conversely, childbearing, particularly having the first child at a younger age, and breastfeeding have protective effects against breast cancer .
Hormonal Influences
Estrogen and Progesterone
Hormonal factors, particularly the levels of estrogen and progesterone, are closely linked to breast cancer risk. High levels of endogenous estrogen and the use of exogenous hormones, such as those in oral contraceptives and hormone replacement therapy, have been shown to increase the risk .
Genetic Factors
BRCA1 and BRCA2 Mutations
Genetic predisposition, especially mutations in the BRCA1 and BRCA2 genes, significantly increases the risk of developing breast cancer. However, these genetic mutations account for only a small percentage of all breast cancer cases .
Environmental and Lifestyle Factors
Chemical Exposure and Pollution
Environmental factors, including exposure to ionizing radiation and various chemical pollutants, have been implicated in breast cancer development. Persistent organic pollutants and endocrine disruptors can affect signaling pathways involved in cancer progression and metastasis .
Diet and Alcohol
Dietary factors, particularly high-fat diets, have been associated with breast cancer, although the evidence is inconsistent. Alcohol consumption is a well-established risk factor, with studies showing a clear link between alcohol intake and increased breast cancer risk .
Physical Activity
Regular physical activity is likely protective against breast cancer. It helps in maintaining a healthy weight and regulating hormone levels, which can reduce the risk.
Viral Infections
Oncogenic Viruses
Recent evidence suggests that certain viruses, such as the mouse mammary tumor virus (MMTV), bovine leukemia virus (BLV), human papilloma virus (HPV), and Epstein-Barr virus (EBV), may play a role in breast cancer development. However, the evidence is not yet conclusive.
Conclusion
Breast cancer is caused by a complex interplay of demographic, reproductive, hormonal, genetic, environmental, and lifestyle factors. While some risk factors, such as age and genetic predisposition, are non-modifiable, others, like diet, physical activity, and exposure to environmental pollutants, can be managed to reduce risk. Continued research is essential to fully understand these factors and develop effective prevention and treatment strategies.
Sources and full results
Most relevant research papers on this topic