The Importance of Genetic Testing for Families With a History of Hereditary Cancers

What Is Genetic Testing?

Genetic testing is a medical test that analyzes an individual's DNA to identify specific changes or variations in their genes, chromosomes, or proteins. It is used to diagnose or determine the risk of developing certain genetic disorders or conditions, as well as to provide information about an individual's genetic makeup and potential response to certain medications.

Even without a hereditary variation, cancer might seem to run in families because common surroundings or lifestyles can cause comparable cancers in family members. However, certain patterns in cancer kinds, non-cancer diseases, and ages at which they first manifest themselves may point to hereditary vulnerability to cancer. Genetic testing can validate the presence of harmful variations and establish if family members have the same variant in genes linked to hereditary cancer risk syndromes. Another genetic test used to direct cancer treatment is tumor DNA sequencing, which identifies genetic mutations that may be inherited or happen at random over the course of a person's lifetime.

What Are the Risk Factors for Hereditary Cancers?

To assess the risk of hereditary cancer syndromes based on family history, it is advisable for individuals to seek guidance from a genetic counselor. Certain features in personal or family medical history, when combined, may suggest a hereditary cancer syndrome. These features include

• Early-onset cancer.

• Multiple types of cancer in one person.

• Cancer in paired organs.

• Multiple relatives with the same cancer type.

• Presence of birth defects associated with inherited cancer syndromes, belonging to a high-risk racial or ethnic group, and several family members with cancer.

Genetic counseling and testing are recommended, especially in family members with a previous or current cancer diagnosis, to confirm the presence of an inherited genetic variant and assess risks for other family members, even if they have not developed cancer. Knowing these risks can aid in preventive measures against future cancers.

How Important Is Genetic Testing for Families With a History of Hereditary Cancers?

Genetic testing plays a crucial role in families with a history of hereditary cancers. Here are some key reasons highlighting the importance of genetic testing in such situations:

• Genetic testing helps identify specific inherited genetic variants associated with hereditary cancer syndromes.

• It evaluates a person's genetic profile-based risk for acquiring a particular form of cancer.

• It offers individualized screening and preventive tactics based on the risk profile of the person.

• It aids in locating at-risk relatives who could also be carriers of the genetic mutation, enabling early discovery and intervention.

• It supports ongoing research and advancements in understanding genetic factors related to cancer.

What Are the Different Types of Genetic Tests for Cancer Risk Assessment?

Hereditary cancer syndromes encompass a diverse range of genetic conditions, with more than 50 known syndromes identified to date. In the majority of cases, these syndromes result from the presence of harmful variants that follow an autosomal dominant inheritance pattern. This means that inheriting just one altered copy of the gene from a parent is sufficient to elevate an individual's risk of developing cancer. Fortunately, genetic testing methods have been developed for the majority of these syndromes, enabling the detection of harmful variants in affected individuals and those at risk.

In addition to the clearly characterized hereditary cancer syndromes, several inherited genetic variations have been related to elevated cancer risks without being directly connected to identified syndromes. For example, it is known that PALB2 variations increase the risk of breast and pancreatic cancer, and CHEK2 variants raise the risk of breast and colorectal cancer. Similar to how RAD51C and RAD51D variations have been connected to higher risks of ovarian cancer, BRIP1 mutations are also linked to ovarian cancer susceptibility.

These inherited genetic variations function as additional cancer risk markers and can direct screening, preventive, and treatment approaches. Since these particular variations can now be genetically tested, people and healthcare professionals may analyze the existence of these genetic markers and choose the best management and monitoring strategies to lower the risk or find cancer at an early stage.

How Is Genetic Testing Done?

Procedure:

• Genetic testing is typically requested by a genetic counselor, doctor, or healthcare provider after reviewing an individual's personal and family medical history.

• There are different types of genetic tests available, including single-gene tests and multigene (panel) tests, which can detect harmful variants in multiple genes simultaneously.

• These tests are performed on a small sample of bodily fluid or tissue, such as blood, saliva, cheek cells, or skin cells, and the samples are sent to specialized laboratories for analysis.

Results:

Genetic test findings can be positive, negative, true negative, uninformative negative, variation of unknown significance, or benign variant, among others.

• Positive Result: The presence of a genetic variation linked to a hereditary cancer susceptibility syndrome is indicated by a positive test result. This finding can support the diagnosis of cancer in a person, direct treatment options, and give other family members crucial information to evaluate their own health risks.

• Negative Result: A negative result means that the specific variant being tested for was not detected. This result is most informative when a specific disease-causing variant is known in the family, indicating that the tested individual has not inherited the variant associated with the tested syndrome. However, a negative result does not completely eliminate the risk of cancer, as other factors may still contribute to the overall risk.

• Variant of Uncertain Significance: Genetic testing may reveal a variant of uncertain significance (VUS), which means that the significance of the genetic change is unclear and does not provide actionable information for healthcare decisions. These variants may be reclassified as more information becomes available.

• Benign Variant: A benign variant is a genetic change that is common in the general population and not associated with an increased risk of disease.

Conclusion:

Genetic testing holds immense importance for families with a history of hereditary cancers. It provides valuable insights into individual and familial cancer risks, enabling personalized screening, prevention, and treatment strategies. By identifying specific genetic variants associated with hereditary cancer syndromes, genetic testing helps guide healthcare decisions, improves outcomes through early detection, and empowers individuals to take proactive measures to reduce their cancer risk.