Background: Cutaneous squamous cell carcinoma (SCC) is the second most common type of skin cancer. Only 2% to 5% of SCCs metastasize; however, those do carry a poor prognosis. Immunohistochemistry (IHC) is widely used by pathologists to characterize skin cancers and provide clinically useful information.
Objective: To evaluate the potential prognostic associations between IHC findings and metastasis in SCC.
Methods: Searches were conducted in MEDLINE via PubMed for articles published between 1999 and 2019. Search criteria included key words "immunohistochemistry" and "cutaneous squamous cell carcinoma." Six hundred and fifty-three articles were returned and screened, which ultimately left 31 for inclusion in our manuscript.
Results: Thirty-one articles analyzed in this review included a discussion of the expression of a particular IHC marker and the associated risk of metastasis and/or clinical utility of IHC markers in SCC, especially metastatic SCC. Markers that had several or more studies supporting clinical utility were E-cadherin, podoplanin, CD8+ T cells, PD-L1, epidermal growth factor receptor, and Cyclin D1.
Conclusion: Immunohistochemistry profiling of SCC may be useful in select cases when providing a prognosis remains challenging and in identification of potential therapeutic targets for high-risk or metastatic tumors.
Copyright © 2020 by the American Society for Dermatologic Surgery, Inc. Published by Wolters Kluwer Health, Inc. All rights reserved.