When doctors talk about biomarkers in cancer, measurable biological indicators that signal the presence or behavior of cancer. Also known as tumor markers, they’re not just lab results—they’re clues that help decide if a treatment will work before you even start it. These markers can be proteins, genes, or even pieces of DNA floating in your blood, and they tell doctors things like how aggressive a tumor is, whether it’s likely to spread, or if a specific drug might help.
Not all cancers have useful biomarkers, but the ones that do are changing how treatment works. For example, HER2, a protein found in some breast cancers tells doctors whether drugs like trastuzumab will work. BRCA1 and BRCA2, genes linked to inherited breast and ovarian cancer risk help identify who needs preventive surgery or targeted therapies. And PD-L1, a marker that shows if the immune system can be activated against cancer helps decide if immunotherapy is worth trying. These aren’t theoretical—they’re used every day in clinics across Canada and beyond.
What’s more, biomarkers aren’t just for diagnosis. They’re used to monitor treatment, catch recurrence early, and even avoid unnecessary chemo. A patient with early-stage breast cancer might get a genomic test like Oncotype DX to see if chemo will actually help—or if it’s safe to skip it. That’s not guesswork. That’s precision medicine. And it’s why so many of the posts here focus on cancer screening, treatment choices, and how drugs interact with your body’s biology. You’ll find real stories here about mammograms, genetic risks, and how blood tests are slowly replacing old-school trial-and-error approaches. What you’ll see below isn’t just a list of articles—it’s a roadmap to understanding how your body’s signals are now guiding your care.
