Dr. Denise Tritz shares how genetic testing can uncover health risks before symptoms appear.
These days, genetic testing is a powerful tool to not only uncover information about a person’s ancestry but also help uncover health risks and potential genetic conditions. By identifying inherited traits and predispositions, genetic testing can help individuals make informed decisions about their health.
Genetics can be linked to the body’s cells, which are classified as the building blocks of the body and are the most fundamental basis of all growth and development throughout the human system. Each cell is comprised of a nucleus and its cytoplasm. The nucleus is essentially the control center of the cell; it is the hub for providing instructions for all functions a cell performs. In the nucleus, chromosomes are structures containing DNA. DNA itself is the genetic material comprised of two threadlike strands linked together. These paired strands carry the instructions for cellular functions in the form of genes.
Each gene is basically a code for a molecule that will direct a function throughout the cell. By studying the genes, medical professionals can better understand many different medical conditions, including cancer.
There are four classes of regulatory genes involved in cell function. These four classes include growth-promoting genes, growth-inhibiting tumor suppressor genes, genes that regulate cell death, and genes involved in DNA repair.
Dr. Denise Tritz, who is a pathologist and the Hospital Medical Laboratory Director with SSM Health St. Mary’s Hospital explains, “Cancer can occur when thereis damage to certain genes in our DNA. We call the dam-age a mutation. The mutation alters the gene so it codesfor a product that can lead to uncontrolled cell growth.”Damage to some of these types of genes can occur inmany types of cancer. However, some mutated genes areonly found in specific forms of cancer.
“Genetic testing allows us to identify if a mutation has occurred in genes related to cancer development,” Dr. Tritz explains. “Identifying the specific mutation present in a tumor can help doctors identify the type of tumor or cancer a patient has, as well as assisting in treatment planning.”
The purpose of cancer genetic testing can be twofold: one, to identify whether a patient is predisposed to inheriting a certain type of cancer, and two, to guide tumor classification and treatment planning.
Cancer can be hereditary or nonhereditary. Hereditary cancers are formed when a mutation occurs in the genes of the egg or the sperm of a parent and is passed onto a child. Examples of this kind of cancer could include breast cancer and colon cancer. The majority (85% to 90%) of cancers, however, are not inherited from a parent but occur as a result of external factors. For example, lung cancer can result from air pollution and/or smoking, and skin cancer can be a direct result of UV radiation exposure.
Genetic testing can aid in tumor typing, which is the process of identifying the specific type of tumor to guide diagnosis and treatment, as well as identifying which mutations are present. Both play a major role in treatment planning for patients with cancer.
“Targeted treatment of cancer, in many instances, is more effective than standard chemotherapy as it is tailored to an individual’s tumor based on its genetic profile.”
Dr. Denise Tritz
Genetic tests performed can also involve looking for specific genes associated with a particular type of cancer, performing multigene panel testing, or even analyzing the entire sequence of certain genes to identify potential mutations. For hereditary cancer screening, samples of saliva or blood are tested. Those who should consider heredity cancer screening include individuals with a family history of multiple or early-onset cancers, rare or aggressive forms of cancer, or any known genetic mutations.
“Every day, scientists are also developing therapies that act at a specific mutation, blocking cancer’s growth,” Dr. Tritz says. “These therapies are called targeted therapies because they only work if the cancer cells contain a specific mutational target. Targeted treatment of cancer, in many instances, is more effective than standard chemotherapy as it is tailored to an individual’s tumor based on its genetic profile.”
There are also other advantages to targeted therapies. Some of the drugs have fewer side effects than traditional chemotherapy; based on the tumor’s genetic profile, the treatment is more personalized rather than a generic regimen; and doctors may combine targeted therapy with other treatment modalities to maximize benefits and success rates.
However, as with all treatments, targeted therapies have some disadvantages. Not all cancer types respond to the targeted therapies currently available; the tumor must have the mutated gene for the treatment to be effective. Another drawback of targeted treatment is the potential loss of response to the drug if a tumor undergoes additional mutations. Some of the targeted drugs also have serious side effects. Lastly, a major current disadvantage of targeted therapy is the high cost of these medications.
While there is no one-size-fits-all approach to testing for, identifying, preventing, or treating cancer, genetic testing can play a major role in early detection, successful treatment, and confirming whether a patient has a predisposition for a certain type of cancer. Targeted treatments can also directly impact the outcome of a patient’s cancer diagnosis. These treatments can be personalized and utilized successfully for many types and stages of cancer.
It is important to understand that though cancer is not universal, and each case is entirely different, genetic testing and targeted treatments can have key roles in how cancer is diagnosed, managed, and treated. Genes might be a microscopic part of the human body, but they have a mighty role throughout all of healthcare.