BlueCross BlueShield of Tennessee Medical Policy Manual

Microarray-based Gene Expression Testing for Cancers of Unknown Primary

Does Not Apply to Commercial Genetic Testing Program effective 6/1/2018


Cancers of unknown primary (CUP) or occult primary malignancies are tumors that have metastasized from an unknown primary source, and make up approximately 2% - 4% of all cancer cases in the United States. These cancers are often accompanied by a poor prognosis.

Conventional methods used to aid in the identification of the origin of a cancer of unknown primary malignancy include a thorough history and physical examination, computed tomography (CT) scans of the chest, abdomen, and pelvis, routine laboratory studies, and targeted evaluation of specific signs and symptoms. Identifying the primary origin of a tumor can dictate cancer specific treatment, expected outcome, and prognosis.

Microarray-based gene expression testing, also known as gene expression profiling, is proposed for use in identifying the original site of cancers of unknown primary. These tests measure the expression of up to 2,000 genes and compare the similarity of the gene expression profile of a cancer of unknown primary to a database of known tissue profiles with histologic morphologies. Examples of these tests include Tissue of Origin®, CancerTYPE ID®, and RosettaGX Cancer Origin™.




The clinical utility of microarray-based gene expression testing for cancers of unknown primary has not been determined. The clinical application of gene expression profiling to direct patient management and tumor site-specific therapy also has not been demonstrated in prospective studies. The impact of this testing on clinical outcomes remains unknown.


Agwa, E., & Ma, P. (2013). Overview of various techniques/platforms with critical evaluation of each. Current Treatment Options in Oncology, 14 (4), 623-633. Abstract retrieved October 13, 2017 from PubMed database.

BlueCross BlueShield Association. Evidence Positioning System. (4:2021). Gene expression-based assays for cancers of unknown primary (2.04.54). Retrieved May 14, 2021 from  (33 articles and/or guidelines reviewed)

Greco, F.A., Lennington, W.J., Spigel, D.R., & Hainsworth, J.D. (2015). Poorly differentiated neoplasms of unknown primary site: diagnostic usefulness of a molecular cancer classifier assay. Molecular Diagnosis & Therapy, 19 (2), 91-97. Abstract retrieved September 19, 2018 from PubMed database.

National Comprehensive Cancer Network. (2021, February). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®). Occult primary (cancer of unknown primary, [CUP]) (V.2.2021). Retrieved May 17, 2021 from the National Comprehensive Cancer Network.

National Institute for Health and Clinical Excellence (NICE). (2010, July). Metastatic malignant disease of unknown primary origin. Retrieved February 28, 2013 from  

Sokilde, R., Vincent, M., Moller, A., Hansen, A., Hoiby, P., Blondal, T., et al. (2014). Efficient identification of miRNAs for classification of tumor origin. The Journal of Molecular Diagnostics, 16 (1), 106-115. (Level 4 evidence)

U. S. Food and Drug Administration. (2012, May). Center for Devices and Radiological Health. 510(k) Premarket Notification Database. K120489. Retrieved February 28, 2013 from

Yoon, H.H., Foster, N.R., Meyers, J.P., Steen, P.D., Visscher, D.W., Pillai, R., et al. (2015). Gene expression profiling identifies responsive patients with cancer of unknown primary treated with carboplatin, paclitaxel, and everolimus: NCCTG N0871 (alliance). Annals of Oncology, 27, 339-344. (Level 3 evidence)




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