FGFR alteration testing is a laboratory method used to look for changes in FGFR genes within cancer cells. These changes can help explain what is driving a tumor’s growth. The results may support diagnosis and may help clinicians consider targeted therapies or clinical trials. It is most commonly used in oncology as part of tumor genomic profiling on biopsy or surgical tissue, and sometimes on blood (“liquid biopsy”).

ESR1 mutation is a change in the **ESR1 gene**, which provides instructions for making the **estrogen receptor**. It is most commonly discussed in **estrogen receptor (ER)-positive breast cancer**, especially in advanced or metastatic disease. Clinicians use ESR1 mutation results to understand **tumor biology** and help guide **treatment selection**. Testing may be done on tumor tissue or through a blood-based “liquid biopsy” that looks for tumor DNA.

PIK3CA testing is a laboratory test that looks for changes (mutations) in the **PIK3CA gene**. It is most often used in oncology to help **characterize a tumor’s biology** and guide treatment planning. The test is commonly performed on **tumor tissue** from a biopsy or surgery, and sometimes on blood as a “liquid biopsy.” Results are interpreted alongside other clinical and pathology information, not on their own.

MET exon 14 skipping is a cancer-related change in how the MET gene is “spliced” when cells make MET messenger RNA. It can lead to abnormal activation of the MET pathway, which can help some tumors grow and spread. It is most commonly discussed as a molecular biomarker in certain solid tumors, especially non-small cell lung cancer (NSCLC). In clinical care, it is mainly used to guide targeted therapy selection and clinical trial options.

ROS1 fusion testing is a lab test that looks for a specific genetic change in cancer cells called a **ROS1 gene fusion**. A fusion happens when part of the ROS1 gene joins with part of another gene and forms an abnormal “hybrid” gene. This change can act like an “on switch” that helps some cancers grow. ROS1 fusion testing is most commonly used in solid tumors such as lung cancer, especially when targeted therapy is being considered.

RET fusion testing is a lab test that looks for a specific genetic change called a **RET gene fusion** in cancer cells. A RET fusion can act like an “on switch” that helps some tumors grow. This testing is commonly used in certain solid tumors, especially lung cancer and thyroid cancer. Results can help clinicians confirm tumor biology and consider targeted treatment options when appropriate.

NTRK fusion testing is a laboratory method used to look for NTRK gene fusions in cancer cells. An NTRK fusion is a specific genetic change that can help drive tumor growth. This testing is commonly used in precision oncology to help guide targeted treatment options. It may be performed on a tumor biopsy sample or, in some cases, a blood sample.

IDH2 testing is a laboratory test that looks for changes (mutations) in the **IDH2** gene. It is most commonly used in **blood cancers**, especially acute myeloid leukemia (AML). The result can help clinicians classify a cancer and consider targeted treatment options. Testing is done on a tumor sample, bone marrow, or blood, depending on the situation.

IDH1 testing is a laboratory test that checks whether a tumor has a change (mutation) in the **IDH1 gene**. It is a type of **molecular pathology** testing that helps describe a cancer’s biology. IDH1 testing is commonly used in cancers such as certain **brain tumors (gliomas)**, **acute myeloid leukemia (AML)**, and **bile duct cancer (cholangiocarcinoma)**. Results can help with diagnosis, classification, prognosis discussions, and treatment planning, including eligibility for some targeted therapies.

BRAF testing is a laboratory test that checks tumor cells (or sometimes blood) for changes in the **BRAF** gene. It is commonly used in oncology to help classify cancers and guide treatment planning. The test looks for specific DNA variants (mutations) that can affect how cancer grows and responds to certain drugs. Results are interpreted by clinicians in the context of the cancer type, stage, and other biomarkers.