Two cancers that begin in the same organ can behave differently at a molecular level. This is one reason modern oncology sometimes uses biomarker or molecular testing before choosing treatment.
What is targeted therapy?
Targeted therapies are medicines designed to act on specific proteins or pathways involved in cancer-cell growth and survival. They are part of precision medicine, but they are not suitable for every patient or every tumour.
Why biomarker testing may be requested
A tumour sample from a biopsy or surgery may be tested for particular proteins, gene changes or other markers. The result can sometimes show that a targeted medicine is relevant, help predict whether a treatment is likely to work, or show that another approach is more appropriate.
A “target” does not always mean a treatment is available
Not every molecular finding has a proven medicine for every cancer type. The meaning of a biomarker depends on the tumour, stage, treatment setting and available evidence. Results need clinical interpretation rather than reading a laboratory report in isolation.
Targeted treatment still requires monitoring
Targeted medicines can cause side effects and resistance can develop over time. Regular appointments, blood tests and scans may be used to monitor safety and response.
This article is for general education and does not replace individualized treatment advice.