National Cancer Awareness Day is observed annually on November 7 in India. Aimed at increasing awareness and encouraging cancer screening, this day, introduced in September 2014, coincides with the birth anniversary of Nobel Laureate Madam Marie Curie for her remarkable contribution to advancements of radiotherapy in treating cancer. 

Cancer is a complex disease with multifactorial causes, including genetic mutations. While some cancers occur sporadically, others have a hereditary component. 

Genetic testing for cancer risk is a powerful tool for identifying individuals at higher risk due to hereditary mutations. Understanding the types of genetic mutations that can cause cancer and recognizing hereditary cancers are vital steps in cancer prevention and early detection. With advances in genetic testing, individuals and healthcare providers have more options to assess and manage cancer risks effectively, improving overall health outcomes. If you suspect you might be at risk or have a family history of hereditary cancer, consult a genetic counsellor or healthcare professional to determine the most appropriate genetic testing option.

Also Read: Oral Cancer: Causes, Symptoms And Treatment

This article explores genetic testing for cancer risk, the types of genetic mutations that can cause cancer, hereditary cancers, and who should consider genetic testing. 

Genetic Mutations and Cancer

Genetic mutations are alterations in the DNA sequence that can lead to uncontrolled cell mutations. These mutations disrupt the intricate control mechanisms that govern cell division and death. Several types of genetic mutations can contribute to cancer development:

Somatic Mutations: 

Somatic mutations occur in non-reproductive cells during a person's lifetime and are not passed on to offspring. They are the primary drivers of sporadic cancers and result from factors like environmental exposures, aging, or random errors in DNA replication.

Germline Mutations: 

Germline mutations are hereditary and present in every cell of an individual's body, including eggs and sperm. These mutations can increase cancer susceptibility if they affect genes responsible for regulating cell growth and DNA repair. Hereditary cancer syndromes often result from these types of mutations.

Also Read: Pancreatic Cancer: Causes, Symptoms And Treatment

Hereditary Cancers and Genetic Mutations:

Certain hereditary cancer syndromes are linked to specific germline mutations. These syndromes significantly increase an individual's risk of developing certain types of cancer. Examples of such genetic cancer syndromes include:

Hereditary Breast and Ovarian Cancer (HBOC): 

These cancers are caused by mutations in the BRCA1 and BRCA2 genes, and this syndrome increases the risk of breast, ovarian, and other cancers.

Lynch Syndrome: 

This condition is associated with mutations in genes like MLH1 and MSH2, raising the risk of colorectal, endometrial, and other cancers.

Familial Adenomatous Polyposis (FAP): 

FAP results from mutations in the APC gene, leading to a high risk of colorectal cancer.

Who Should Get Genetic Testing for Cancer Risk?

Genetic testing for cancer risk is recommended for individuals who meet specific criteria:

Personal or Family History: 

Individuals with a firm or family history of specific cancers may be candidates for genetic testing. This includes individuals with multiple close relatives who have had cancer, especially at a young age.

Specific Ethnic Backgrounds: 

Some genetic mutations are more prevalent in certain ethnic groups. For instance, the BRCA mutations are more common in individuals of Ashkenazi Jewish descent.

Early-Onset Cancers: 

If someone has been diagnosed with cancer at a younger age than typical for that cancer type, genetic testing may be considered.

Types of Genetic Tests for Cancer Risk

Genetic testing for cancer risk comes in several forms, including single mutation testing, single gene testing, and panel tests.

Single Mutation Testing: 

This type of testing is used when a known, specific genetic mutation is suspected. It is most commonly employed in high-risk families where a particular mutation is prevalent.

Single Gene Testing: 

Single-gene testing focuses on a specific gene associated with a known hereditary cancer syndrome. It's used when there's a strong suspicion of a particular syndrome. For example, BRCA1 and BRCA2 testing assesses breast and ovarian cancer risk.

Panel Tests: 

These are comprehensive genetic assessments that analyze multiple genes associated with hereditary cancer syndromes. These tests are more inclusive and can uncover potential risks for various types of cancer in one go, making them a valuable choice for some individuals.

Also Read: PET Scan: Know Why It Is Done And What To Expect?

How Accurate Are Genetic Tests for Cancer? 

Genetic testing for cancer risk has come a long way regarding accuracy and reliability. The accuracy of these tests depends on various factors, including the type of test, the quality of the laboratory conducting the analysis, and the specific mutation being tested. In general, single mutation and single gene tests are highly accurate when evaluating the targeted mutation. Panel tests, which analyze multiple genes, are also highly accurate when identifying mutations within the tested genes.

However, it's essential to recognize that while these tests can detect genetic mutations associated with cancer risk, they do not definitively predict whether an individual will develop cancer. The presence of a mutation elevates the risk, but it doesn't guarantee the disease will manifest. Additionally, false negatives and false positives can occur. False negatives may result from not detecting a specific mutation, while false positives can create unnecessary anxiety and interventions.

Therefore, interpreting genetic test results is a nuanced process often involving genetic counsellors and healthcare professionals who can provide context and guidance based on an individual's family history, lifestyle, and other risk factors. The evolving field of genetic testing continues to refine its accuracy and predictive power, contributing to better-informed healthcare decisions and personalized cancer prevention strategies.