Breast cancer occurs when cells in the breasts begin to multiply uncontrollably, resulting in the formation of tumors, and October is Breast Cancer Awareness Month. If left untreated, cancerous cells can spread throughout the body and be fatal. This type of cancer is a global health concern, as it affects people of all ages and genders.
Early detection is essential in the fight against breast cancer, as the earlier it is detected, the greater the chances of successful treatment. Despite advances in medicine, breast cancer remains one of the leading causes of cancer death worldwide.
In 2020, an estimated 2.3 million new cases of breast cancer were diagnosed worldwide. This disease does not discriminate, affecting both men and women. However, women have a significantly higher lifetime risk of developing breast cancer.
In this blog, we will explain breast cancer in detail: from its risk factors, the influence of genetics, and detection methods.
Populations with a higher predisposition to breast cancer
Among women in developing countries, breast cancer remains the leading cause of death (3). Furthermore, the incidence varies considerably among ethnicities (4); for example, the disease is more prevalent among Ashkenazi Jews due to the high degree of consanguinity within this population group.
Breast cancer risk factors
- Aging: The risk of breast cancer increases with age, being more common in women over 40.
- Obesity: Being overweight, obese, and having a sedentary lifestyle are linked to a higher risk of developing breast cancer.
- Excessive alcohol consumption has been associated with an increased risk of breast cancer.
- Family history of cancer: Having close relatives with a history of breast cancer may increase the risk.
- Radiation Exposure: A history of radiation exposure, especially to the chest area.
- Reproductive History: Factors such as the age of onset of menstrual periods and the age at first pregnancy can influence the risk.
- Smoking: Smoking tobacco has been linked to an increased risk of breast cancer.
- Post-Menopausal Hormone Therapy: Prolonged use of hormone replacement therapy after menopause may increase the risk.
Breast cancer in men
Although breast cancer is commonly associated with women, it's important to note that it can also affect men, although it is much less frequent, especially in those over 60. This is because, compared to women, men have less developed breast tissue, meaning there are fewer glandular cells where a malignant tumor could develop. Consequently, the incidence of breast cancer in men is lower than 5%.
Classification and Oncogenes
An oncogene is an abnormal or activated gene that originates from the mutation of an allele of a normal gene called proto-oncogene. Oncogenes are responsible for the transformation of a normal cell into a malignant one that will develop a specific type of cancer. cancer.
In breast cancer we find different types depending on the absence or presence of estrogen/progesterone receptors (5):
- Hormone receptor positive/ERBB2 negative
- ERBB2 positive
- Triple negative (tumors that lack the 3 standard molecular markers)
Regarding oncogenes, one of the most important is HER2, associated with breast cancer. For this reason, its progression is studied and analyzed both in terms of survival and its potential for recurrence (6), that is, the possibility that the tumor may reappear.
Evolution and approach to the disease
This type of cancer often progresses silently, so most diagnoses are made during routine medical examinations. Occasionally, patients present with a lump in the nearby area or in the breast itself. (2)
Looking at historical data, one positive finding is that the mortality rate has been steadily declining for the last thirty years (7). It has also been shown that many breast cancers are non-metastatic at the time of diagnosis (5). Furthermore, some research suggests that not all cells within breast cancer have the capacity to develop into tumors (8).
If we return to the classification and take, for example, the type triple negative, We can say that this type has the highest probability of recurrence, although, conversely, it has a high survival rate compared to the other types. In any case, it is essential to identify and understand in depth the patterns that each of these types exhibits. In this way, clinical strategies can be increasingly personalized in order to establish increasingly effective treatments.
Treatments
It is important to keep in mind that there are different types of breast cancer, so treatments will not always be the same. Currently, surgery, radiotherapy, chemotherapy, hormone therapy, targeted therapy, and immunotherapy are used (9)
The most common treatment is with cyclophosphamides, but apart from these, according to recent research, trastuzumab, as an adjunct to chemotherapy, is offering good survival results (10). However, gene expression analysis in breast cancer has not yet allowed for the establishment of therapeutic strategies tailored to each individual (11).
Furthermore, it is important to emphasize the need to choose the right treatment, as side effects can sometimes occur. (9)
Detection, diagnosis and prevention
In genetics, breast cancer cannot be understood without discussing genomic instability, an essential concept in understanding its development (12). Genomic instability is the increased tendency to present genetic mutations or other genetic changes that appear during cell division and is often associated with many types of cancer.
Among the most important genetic tools we found, two are especially noteworthy:
- MicroRNAs are diagnostic biomarkers. For example, they have recently been discovered in breast cancer. miR-99a-5p (13), which has been identified as a good tool for early detection of breast cancer.
- Genetic tests, which can be preventive (when they analyze some of the genes involved in a pathology) or diagnostic (when they analyze all the DNA that affects said pathology).
The genetic testing Zogen's tools allow for more informed decisions that help people improve their well-being. Specifically, our Health test considers the BARD1, BRCA1, BRCA2, BRIP1, PALB2, PTEN, TP53, CHEK2, CDH1, and ATM genes, which are directly related to breast cancer (14). We also have genomic sequencing tests that can analyze a greater number of genes, and even select them to understand the type of cancer, in order to develop personalized treatments, or determine their effectiveness.
Hereditary breast cancer accounts for approximately 101% of all breast cancer cases, meaning that there are genes with mutations associated with this type of malignant tumor.. Specifically, people with a mutation in the BRCA1 or BRCA2 genes have a higher risk of developing breast cancer and even ovarian cancer (9).
At Zogen, we try to raise awareness of the importance of taking a genetic test, as it can help many people identify if they have genes associated with this type of cancer in their genetic makeup, especially if there is a family history of this disease.
Literature:
- World Health Organization. 2021. https://www.who.int/es/news-room/fact-sheets/detail/cancer
- Torre, LA, et al. (2015). Global cancer statistics, 2012. CA: A Cancer Journal for Clinicians, 65.
- Momenimovahed, Z., & Salehiniya, H. (2019). Epidemiological characteristics of and risk factors for breast cancer in the world. Breast Cancer: Targets and Therapy, 11, 151 – 164.
- Waks, A.G., & Winer, E. (2019). Breast Cancer Treatment: A Review. JAMA, 321, 288–300.
- Slamon, D., et al. (1989). Studies of the HER-2/neu proto-oncogene in human breast and ovarian cancer. Science, 244 4905, 707-12 .
- DeSantis, C., et al. (2019). Breast cancer statistics, 2019. CA: A Cancer Journal for Clinicians, 69.
- Veer, LJ, et al. (2002). Gene expression profiling predicts clinical outcome of breast cancer. Nature, 415, 530-536.
- Al-Hajj, M., et al. (2003). Prospective identification of tumorigenic breast cancer cells. Proceedings of the National Academy of Sciences of the United States of America, 100, 3983 – 3988.
- Slamon, D., et al. (2001). Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2. The New England journal of medicine, 344 11, 783-92. .
- Yeow, ZY, et al. Targeting TRIM37-driven centrosome dysfunction in 17q23-amplified breast cancer. Nature 585, 447–452 (2020). https://doi.org/10.1038/s41586-020-2690-1
- ACS Sens. 2021, 6, 3, 1022–1029. February 18, 2021. https://doi.org/10.1021/acssensors.0c02222
- Health Report. (2021). 24Genetics
