How are tumor marker tests performed for breast cancer?
Tumor marker tests for breast cancer are typically performed on tissue samples obtained through a biopsy or during surgery when a tumor is removed. A pathologist examines these samples under a microscope to check for cancerous cells and determine important markers.
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How are tumor marker tests performed for breast cancer?
Tumor marker tests for breast cancer are typically performed on tissue samples obtained through a biopsy or during surgery when a tumor is removed. A pathologist examines these samples under a microscope to check for cancerous cells and determine important markers.
The main tests used include:
- Immunohistochemistry (IHC): This test estimates the amount of specific proteins like HER2 on the outside of cancer cells. The tissue is placed on a glass slide, and a chemical solution containing antibodies is added. If the protein is present, the antibody attaches to it and causes the cells to change color.
- Fluorescence in situ hybridization (FISH): This measures the number of specific genes like HER2 inside the cells.
These tests help identify hormone receptor status (estrogen and progesterone receptors) and HER2 status, which are crucial for determining the best treatment options. Some tumor marker testing can also be performed through blood tests.
The results show whether your cancer cells have receptors that respond to hormones or have excess HER2 protein, which directly influences your treatment plan.
December 17, 2025
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