Immunotherapy for a Cancer of Unknown Primary
Immunotherapy is the use of medicines that help a person’s own immune system find and destroy cancer cells. It may be used to help treat some cancers of unknown primary (CUP).
Using immunotherapy for cancers of unknown primary (CUP)
Immunotherapy is the use of medicines that help a person’s own immune system find and destroy cancer cells. It may be used to help treat some cancers of unknown primary (CUP).
Immunotherapy drugs have been particularly successful in the past decade in treating lung cancer, melanoma, and several other types of cancer. Recent clinical trials in patients with cancers of unknown primary (CUP) showed a benefit in using immunotherapy, particularly if next-generation sequencing (NGS) testing showed molecular abnormalities that could be used to help determine the tissue of origin, such as high microsatellite instability (a lot of mutations in repeated DNA sequences) or high tumor mutational burden (meaning a lot of gene mutations were found in the tumor).
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Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Posner A, Sivakumaran T, Pattison A, Etemadmoghadam D, Thio N, Wood C, et al. Immune and genomic biomarkers of immunotherapy response in cancer of unknown primary. J Immunother Cancer. 2023 Jan;11(1):e005809. doi: 10.1136/jitc-2022-005809. PMID: 36720497; PMCID: PMC10098268.
Raghav K, Overman M, Poage GM, Soifer HS, Schnabel CA, Varadhachary GR. Defining a distinct immunotherapy eligible subset of patients with cancer of unknown primary using gene expression profiling with the 92-gene assay. Oncologist. 2020 Nov;25(11):e1807-e1811. doi: 10.1634/theoncologist.2020-0234. Epub 2020 Sep 23. PMID: 32893931; PMCID: PMC7648339.
Last Revised: May 27, 2025
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