Biomarker (includes genetic marker, genomic marker, molecular marker, or signature marker)

A biomarker is something doctors can measure in the body to help understand what’s happening with your health. Biomarkers can be found in your blood, other body fluids, or tissues and provide clues about what’s going on inside the body. It can show if the body is working normally, if a disease like cancer is developing, or how well a treatment is working.

For example, cancer cells can release small pieces of DNA, called ctDNA, into the blood and doctors can sometimes analyse these to detect cancer early or decide if a treatment plan needs to be changed.

Doctors may use biomarkers to:

• Detect cancer early or confirm a diagnosis
• Monitor how a disease is changing over time
• Predict how well a treatment might work
• Check if the body is responding to treatment

Biomarkers are an important part of personalised medicine, helping ensure people get the most effective treatment for their cancer

• Molecular biomarker: A measurable biological molecule that gives information about health or disease. Molecular biomarkers can include DNA, RNA, proteins or other molecules found in blood, other body fluids or tissues.
• Liquid biopsy: A test that looks for biological substances or factors in blood or other body fluids, including tumour material such as circulating tumour DNA (ctDNA). Liquid biopsies may help detect cancer, monitor disease or understand how well treatment is working.