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.

NRAS testing is a laboratory test that looks for changes (mutations) in the **NRAS** gene in cancer cells. It is a type of **molecular or biomarker testing** used to better understand a tumor’s biology. It is commonly performed on tumor tissue and sometimes on blood using a “liquid biopsy” approach. Results can help clinicians refine diagnosis and guide treatment planning in selected cancers.

KRAS testing is a lab test that checks a tumor for changes (mutations) in the KRAS gene. It is commonly used in solid tumors to help classify the cancer and guide treatment planning. It usually uses tissue from a biopsy or surgery, and sometimes uses a blood sample (liquid biopsy).

EGFR mutation testing is a laboratory test that looks for specific DNA changes in the EGFR gene. It is most commonly used in certain solid tumors, especially non-small cell lung cancer. The goal is to identify tumor features that may affect diagnosis and treatment planning. Testing can be done on tumor tissue or sometimes on a blood sample.

ALK FISH is a laboratory test that looks for changes in the ALK gene in tumor cells. It uses fluorescent markers to detect ALK gene rearrangements under a microscope. It is most commonly used in certain lung cancers and some rare tumors and lymphomas. Results can help clinicians match a cancer to targeted treatments when appropriate.