About RET Fusion Cancer
RET fusion cancers are caused by chromosomal rearrangements that join the RET gene (which encodes a receptor tyrosine kinase normally involved in cell growth and nervous system development) with a partner gene. The resulting fusion protein is constitutively active, driving cancer growth independent of normal signaling controls. The most common RET fusion partner in lung cancer is KIF5B, though many other partners have been identified.
RET fusions are most frequently found in non-small cell lung cancer (1-2% of cases) and papillary thyroid cancer (7-12% of cases, higher in pediatric patients), and less commonly in other tumor types including colorectal, breast, and other cancers. Because RET fusions are actionable across tumor types, comprehensive genomic profiling is essential for identifying these patients.
Selective RET inhibitors have transformed treatment. Selpercatinib (Retevmo, Eli Lilly) received full FDA approval in 2022 for RET fusion-positive NSCLC after a phase 3 trial (LIBRETTO-431) demonstrated superiority over chemotherapy as first-line treatment, establishing it as the standard of care. Selpercatinib also has tissue-agnostic accelerated approval for RET fusion-positive solid tumors, with durable response rates of 60-85% across previously treated and treatment-naive patients. Pralsetinib (Gavreto) also received full FDA approval in 2023 for RET fusion-positive NSCLC, though it is not approved for other tumor types. These selective inhibitors have largely replaced older multikinase inhibitors and chemotherapy for RET fusion-positive cancers.
Common Symptoms of RET Fusion Cancer
Recognizing the signs of RET Fusion Cancer early can lead to faster diagnosis and better outcomes. Symptoms may vary in severity from person to person. If you or a loved one are experiencing any of the following, consider speaking with a specialist.
- Symptoms depend on the tumor type and location
- For lung cancer: persistent cough, shortness of breath, chest pain, coughing up blood
- For thyroid cancer: a neck lump, hoarseness, difficulty swallowing
- Fatigue and unexplained weight loss
- Bone pain, headaches, or neurological symptoms if the cancer has spread
- Some RET fusion cancers are discovered incidentally on imaging
Who RET Fusion Cancer Affects
RET fusions in NSCLC tend to occur in younger patients (median age ~60), never-smokers or light smokers, and are slightly more common in women, though they can occur in anyone. RET fusion-positive papillary thyroid cancer can occur at any age.
No clear ethnic predisposition is established, though detection rates vary by how commonly genomic testing is performed. The fusion is a somatic (acquired) event, not inherited, distinguishing it from germline RET mutations that cause hereditary medullary thyroid cancer.
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Side Effect Explorer
Real-world side effect reports from the FDA Adverse Event Reporting System (FAERS). Includes both FDA-approved drugs and investigational therapies from active clinical trials. Click any drug to see what patients reported.
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Genetic Testing
Genetic testing can confirm a diagnosis, guide treatment decisions, and identify family members who may be at risk.
The RET gene page lists every condition Orphanet links to the gene and the open trials that name it.
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Trusted RET Fusion Cancer Resources
Reputable organizations and medical references for learning more about RET Fusion Cancer, including disease registries, foundation resources, and clinical guidelines.