The genetics of hereditary cancer.
Cancer is a disease we have lived with for centuries, and it is currently one of the leading causes of death worldwide. This high incidence means that most people will have some relatives with cancer, especially in large families. Age is the greatest risk factor for most cancers. Lifestyle, environment, and/or minor genetic variations may also be related to cancer risk in some families.
Between 5 and 101% of all cancer cases are linked to genetic alterations that are inherited, meaning they are passed from parents to children. Having an inherited genetic change does not always mean that one is destined to develop cancer, but rather that there is a higher risk of developing a certain type or types of cancer. New genes that are hereditarily associated with different types of cancer are becoming increasingly well understood.
When does hereditary cancer occur?
Hereditary cancer occurs when a genetic change that increases the risk of cancer is passed from parents to children. Being born with this change means a person has a higher chance of developing specific types of cancer, and these cancers may occur at a younger age than in people without the change. Currently, it is recommended to study a larger number of genes using more efficient sequencing of multigene panels.
Some types of cancer have specific characteristics that suggest a risk may have been inherited from a parent, even when there is no significant family history of cancer. Examples include:
- Breast cancer described as "triple negative" (negative results when the presence of certain proteins in the tumor tissue is examined in the biopsy analysis)
- Ovarian cancer described as high-grade serous (this includes similar cancer in the fallopian tubes or peritoneum).
- Cancer in the colon or uterus (endometrium) that is described as lacking certain proteins when tests are performed on the tumor.
- Some people who undergo a colonoscopy have more polyps than expected, or unusual polyps, which may also suggest a risk of hereditary cancer.
The main objective of genetic diagnosis of a predisposition to hereditary cancer is the intervention and monitoring of the affected patient and their family with the purpose of reducing mortality caused by cancer.
What are genetic tests used for in relation to cancer?
Genetic testing related to cancer guides decision-making. The purpose of performing a test for hereditary cancer predisposition is to recommend monitoring and prevention measures tailored to the identified risk and to inform individuals and their families to discuss different preventive measures, ranging from strict periodic monitoring to—in some cases—recommending preventive surgery (for example, preventive mastectomy, colon resection, removal of ovaries and fallopian tubes, etc.).
A person should consider genetic testing for hereditary cancer if:
- She has several first-degree relatives (mother, father, siblings, children) with cancer.
- Many relatives on one side of your family have had the same type of cancer.
- If you know that a certain type of cancer in your family is related to a genetic alteration.
- A family member has more than one type of cancer or bilateral cancer, for example, in both breasts.
- Family members have had cancer at a younger age than normal for that type of cancer.
- A family member has a rare cancer, such as breast cancer in a man or retinoblastoma (a type of eye cancer).
- A physical finding that is related to hereditary cancer (such as having many polyps in the colon).
- One or more family members have already had a genetic test that found a genetic alteration.
If you have concerns about cancer in your family, talk to your doctor. Bring any information you have about family members who have had cancer. Also, talk to your relatives to find out if anyone has already started treatment. Reviewing this information can help you and your doctor decide whether treatment is necessary. genetic test.
Learn more about our tests preventive measures in cases of suspected hereditary cancer.
