Tissue Biopsy
What is a tissue biopsy?
A tissue biopsy is the removal of a small sample of tumor tissue for laboratory analysis. It is the most established method for identifying cancer type, stage, and genetic alterations. For MET-altered cancers, tissue biopsy is often the preferred method for comprehensive molecular profiling because it provides the most complete picture of the tumor’s biology.
Tissue samples can be analyzed using next-generation sequencing (NGS), immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and other methods — making a single biopsy potentially informative for multiple biomarkers at once.
Types of tissue biopsy
Core needle biopsy: a hollow needle removes a cylinder of tissue from the tumor. This is among the most common methods and provides enough material for broad molecular testing.
Bronchoscopy: a thin, flexible tube is passed through the nose or mouth into the airways to reach tumors in or near the lung. Samples can be collected during the procedure.
Surgical biopsy: a larger tissue sample removed during surgery. Used when needle biopsy is not possible or when more tissue is needed.
Endoscopic ultrasound (EUS) or endobronchial ultrasound (EBUS): ultrasound guidance is used to reach lymph nodes or tumors near the airways or esophagus that are difficult to access otherwise.
Why it matters for MET patients
MET overexpression by IHC and MET amplification by FISH both require tissue samples — these tests cannot be done on blood alone. If you have not had a tissue biopsy, or if your original biopsy material has been exhausted, talk with your oncologist about whether a repeat biopsy is appropriate.
Save your tissue.
Ask your pathologist how much biopsy material remains after initial testing. Preserving tissue for future molecular testing is important, especially as new targeted therapies become available or if your cancer progresses and re-testing is needed.
Limitations
A single tissue biopsy reflects only one part of the tumor at one point in time. Tumors can be heterogeneous — meaning different parts may have different mutations. Repeat biopsy at progression can capture new alterations that have developed since initial diagnosis.