Oncogenetics: How Genes Affect the Risk of Cancer

What is oncogenetics?

Oncogenetics is a branch of genetics that studies inherited and acquired mutations in genes that may influence the risk of developing malignant tumors. It is about inherited gene variants, which are passed down from parents, and about mutations that occur throughout life due to environmental influences, viruses, and unhealthy lifestyle.

Thanks to oncogenetic studies, it is possible to assess individual susceptibility to cancer, timely detect critical changes at the molecular level and develop a personalized prevention and treatment strategy.

What genes are associated with oncology?

The most well-known are genes BRCA1 і BRCA2, mutations in which increase the risk of breast and ovarian cancer. But there are other important genes:

• TP53 — cell cycle regulation, mutation is associated with many types of cancer

• APC — associated with the development of colorectal cancer

• MLH1, MSH2, MSH6 — DNA repair genes associated with Lynch syndrome

• CDH1 — linked to stomach and breast cancer

• PTEN — tumor growth suppressor

Oncogenetic testing can detect the presence of mutations in these and other genes.

What is a genetic test for cancer susceptibility?

A genetic test is a laboratory test that analyzes a patient's DNA to detect mutations that increase the risk of developing certain types of cancer. The test is usually performed on venous blood or cheek mucosal epithelium.

Indications for testing:

• Having multiple cases of cancer in the family (especially at a young age)

• Combination of different types of tumors in one relative (for example, breast and ovarian cancer)

• Cancer cases in young people (<40 years)

• Planning preventive measures or choosing treatment tactics

• Desire to assess individual risk

What are the benefits of oncogenetic testing?

• Risk assessment — understanding the individual likelihood of disease

• Prevention — possibility of regular monitoring or preventive measures

• Personalized therapy — selection of effective treatment methods

• Family counseling — relatives can also get tested

• Reducing cancer anxiety — in the absence of mutations

Table: Examples of genes and cancer types

Can cancer be prevented by knowing genetic risks?

Thanks to oncogenetic screening, a person can get a colonoscopy, mammogram, MRI, or other tests on time to detect tumors at an early stage. In some cases, drug prophylaxis or even preventive surgery is recommended.

For example, women with the BRCA1 mutation have up to an 80% risk of developing breast cancer — and can discuss with their doctor the issue of prophylactic mastectomy or regular surveillance.

Recommendations from WHO and international associations

According to the recommendations WHO, NCCN and ESMO, genetic testing recommended:

• all patients with suspected hereditary forms of cancer

• family members with identified mutations

• for making decisions about the choice of therapy (targeted drugs, PARP inhibitors)

Genetic counseling is a mandatory component of such testing.

Limitation

• Testing does not guarantee that cancer will definitely occur.

• Cost remains high for individual panels

• Results can cause psychological distress

• Not all mutations have clinical significance - specialist interpretation is required

Oncogenetics is not only about risks, but also about opportunities. It gives us a chance to act proactively, change the scenario, and preserve our health—for ourselves and for future generations.