Is breast cancer really a cancer that is already written into our genes?

Breast cancer, like all other cancers, is caused by normal cells undergoing genetic mutations and developing into cancer cells.

However, it takes time for normal cells to become cancer cells.

A large number of cells divide in our body every day. Every time a cell divides, the genetic material is evenly distributed between the two cells.

Errors are inevitable during cell division, so gene mutations occur, but only when mutations occur in key genes, and about 10 mutations must accumulate to achieve this transformation.

Because mutations are random, the longer you live, the higher the chance that more than 10 mutations will accumulate in these key genes. In other words, if we live long enough, everyone will get cancer. The same is true for breast cancer.

So, will this mutated cancer gene be inherited?

A few years ago, the famous Hollywood movie star Angelina Jolie confirmed through genetic testing that she had inherited a mutated breast cancer susceptibility gene BRCA1 from her mother. In order to reduce the risk of breast cancer, she underwent a preventive bilateral mastectomy. BRCA here is the abbreviation of the English professional term Breast Cancer Susceptibility Genes, which is one of the key genes in the formation of breast cancer cells.

If Angelina Jolie's mother had accumulated 8 mutations in BRCA1 before giving birth to her, and then at the age of 50, the 10 necessary mutations were gathered, her mother would develop breast cancer. As a daughter, Angelina Jolie was born with these 8 mutations due to genetic reasons. Therefore, compared with healthy people, she has a much higher chance of developing breast cancer after gathering 10 mutations.

However, even if there is a pathogenic mutation in the BRCA1 gene, it does not necessarily mean that Angelina Jolie will definitely develop breast cancer in her lifetime. Similarly, if a person is found to have no pathogenic mutation in the BRCA gene, it does not mean that they will not develop breast cancer in their lifetime. Under long-term exposure to certain risk factors in the environment, originally normal cells may also develop into cancer cells due to gene mutations.

So, are there any risk factors that have been proven to be associated with breast cancer?

The answer is yes. Currently, we know that the risk factors associated with breast cancer include: early menarche (55 years old); unmarried, childless, late childbearing, and no breastfeeding; failure to promptly diagnose and treat benign breast diseases; atypical breast hyperplasia confirmed by hospital biopsy (or tissue examination); high-dose radiation exposure to the chest; long-term use of exogenous estrogen; postmenopausal obesity; long-term excessive drinking; smoking; excessive mental stress; family history of breast cancer and people carrying mutation genes related to breast cancer.

It can be seen that in addition to the unchangeable genetic factors and age, other factors such as excessive mental stress, unbalanced diet, lack of exercise, etc., which are closely related to our unhealthy lifestyle, are also closely related to the occurrence of breast cancer. The latest medical research also reveals that about 2/3 of cancers are caused by the accumulation of random errors in the process of cell replication. Another 1/3 is caused by lifestyle habits.

In other words, even if we are unlucky enough to inherit a mutated cancer susceptibility gene, we still have the opportunity to minimize the probability of gene mutation by adjusting our lifestyle, thereby effectively preventing breast cancer.

Note: There is no copyright issue for the pictures in this article

Author: Chu Yi, Shanghai University of Medicine and Health Sciences

About the Author

Chu Yi

She is a full-time teacher at the Practice Teaching Center of Shanghai Health Medical College, a Chinese technical guidance expert for the 45th World Skills Competition, a member of the expert group of the China "Standardized Patient" (SP) Practice Teaching Steering Committee, and a member of the CSPC (Youth Expert Committee) of the Health Science and Technology Working Committee of the China International Science and Technology Promotion Association. She has been engaged in teaching courses such as "Geriatric Nursing", "Internal and Surgical Nursing" and "Community Nursing" for a long time.

Funded by Shanghai Science and Technology Commission's Science Popularization Project

(Project No.: 20DZ2311100)