A CLOSER LOOK AT THE SIGNALS DRIVING PRECISION MEDICINE
In the world of personalized medicine, biomarkers are pivotal. These biological markers, which can include genes, proteins, or other molecules, help tell us what’s happening inside the body—whether it’s a normal process or an indication of disease. Essentially, biomarkers act as signals, offering clues that can aid in diagnosis, predict how a disease might progress, and guide tailored treatment plans, especially for complex diseases like cancer.
What are Biomarkers?
Biomarkers are measurable substances in our bodies that reflect the state of our health. They can be found in blood, urine, tumour tissue, or other bodily fluids and tissues. For example, cholesterol levels serve as a biomarker for heart disease risk, while specific proteins or DNA mutations are biomarkers for certain types of cancer.
Not all biomarkers are associated with disease. Some simply indicate a biological process at work, like hormone levels during puberty or pregnancy. However, in medical contexts, we often talk about biomarkers as they relate to diseases, such as cancer, cardiovascular disease, or autoimmune conditions. These biomarkers are valuable because they help physicians identify specific aspects of a disease that can be targeted for treatment.
Biomarkers in Cancer: Decoding the Tumour’s Unique Biology
Cancer biomarkers are especially important because they help physicians understand the unique genetic and molecular profile of a tumour. Biomarkers can be either “produced” by the cancer itself or come from the body’s response to the presence of cancer. For example:
Proteins like PSA (prostate-specific antigen) can indicate prostate cancer.
Gene mutations in BRCA1 or BRCA2 are linked to a higher risk of breast and ovarian cancers.
Gene expression patterns can also tell us how aggressive a cancer might be or how it will respond to certain drugs.
Cancer biomarkers are integral to the practice of precision medicine, where treatments are customized to the individual based on the specific characteristics of their disease. For instance, a tumour with high levels of the HER2 protein—a biomarker for certain breast cancers—might be treated effectively with therapies designed to block HER2, slowing tumour growth.
How Are Biomarkers Used in Treatment Decisions?
By analyzing a patient’s biomarkers, doctors can make better-informed decisions about which treatments are likely to work. Here’s how biomarkers impact cancer treatment:
Predicting Response to Therapy: Certain biomarkers can suggest how well a treatment may work for a specific individual. For example, tumours with an abundance of the HER2 protein may respond well to HER2-targeted drugs, while high levels of the protein ERCC1 in a tumour may indicate resistance to certain chemotherapy drugs.
Guiding Targeted Therapy: Many cancer treatments now target specific biomolecules. If a tumour expresses a particular biomarker, doctors can select drugs that directly target those characteristics. This approach makes treatment more effective and reduces side effects, as it minimizes impact on healthy cells.
Understanding Disease Progression: Some biomarkers reveal how aggressive a cancer might be, helping doctors forecast the disease’s course. For example, high levels of certain biomarkers may indicate a fast-growing cancer, prompting a more aggressive treatment plan.
Monitoring Treatment Effectiveness: Biomarkers can also be used to track how well a patient is responding to treatment. If levels of a biomarker decrease during therapy, it could suggest that the treatment is working.
The Science Behind Biomarkers: DNA, RNA, and Proteins
Understanding the structure of DNA, RNA, and proteins is key to knowing how biomarkers function in cancer and other diseases:
DNA (Deoxyribonucleic Acid): DNA contains the instructions for building every cell in the body. Certain mutations in DNA can be biomarkers for cancer risk or prognosis.
RNA (Ribonucleic Acid): RNA transcribes and translates the instructions in DNA to create proteins. Different RNA types serve various roles, such as creating the blueprint (mRNA) or transporting amino acids (tRNA) for protein synthesis.
Proteins: These complex molecules perform a vast range of functions, from immune responses to tissue repair. Specific proteins, such as cytokines or enzymes, can be biomarkers indicating inflammation, disease, or specific cellular processes.
Categories of Cancer Biomarkers
Cancer biomarkers vary widely in their functions and types. Here are three main types that help guide treatment and prognosis:
Biomarkers That Trigger Abnormal Cell Growth: These biomarkers indicate when a cell is multiplying abnormally. For instance, an excess of the HER2 protein can drive tumour growth, signaling a need for targeted treatments to slow cell proliferation.
Biomarkers That Aid Treatment Delivery: Some biomarkers help therapies reach their target more effectively. For example, SPARC (Secreted Protein, Acidic, Cysteine-Rich) can aid in transporting albumin-bound drugs to cancer cells, enhancing the impact of these treatments.
Biomarkers That Disrupt Treatment Action: Other biomarkers can resist or “block” a treatment’s intended effect. For instance, the protein ERCC1 helps repair DNA damage, which can reduce the effectiveness of chemotherapy drugs designed to damage tumour DNA.
Genetic Biomarkers (GERMLINE) vs. Cancer (SOMATIC) Biomarkers
It’s important to distinguish between biomarkers that indicate inherited cancer risk and those that reflect a cancer’s unique genetic makeup. While mutations in genes like BRCA1 and BRCA2 signal an increased cancer risk, most cancer biomarkers represent changes within the tumour itself, rather than in a person’s inherited DNA. This distinction is critical, as treatments often target the unique mutations or molecular characteristics within cancer cells.
Testing for Biomarkers: Personalized Cancer Treatment Plans
Biomarker testing involves collecting a sample—such as blood or tissue from a tumour—and sending it to a laboratory for analysis. Scientists measure the levels of relevant biomarkers to identify which treatments might work best. The results guide doctors in developing a personalized treatment plan, matching the therapy to the tumour’s specific traits, thanks to extensive research and clinical trials.
The Future of Biomarkers in Medicine
With rapid advances in genomic technology, biomarker discovery is accelerating, opening up new possibilities for highly personalized cancer treatments. As researchers identify more biomarkers, the potential for treatments tailored to each individual’s unique genetic profile grows significantly. This shift aims to move beyond treating cancer based solely on its location, instead focusing on its specific genomic characteristics. Such a precision medicine approach offers the promise of better patient outcomes by aligning therapies more closely with the unique biology of each tumour type.
During #KNOWvember, let’s celebrate the promise of precision medicine, where biomarkers bring us closer to understanding and fighting diseases in ways we never thought possible. #KNOWYOURGENOMICS #PMAM24