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Filaggrin expression via immunohistochemistry in basal cell carcinoma and squamous cell carcinoma
Author(s) -
Vanderbeck Kaitlin,
Orr Christine E.,
Parvinnejad Nikoo,
Wang Tao,
Bradshaw Scott,
Wang Ami,
Asai Yuka
Publication year - 2021
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.13975
Subject(s) - filaggrin , immunohistochemistry , pathology , tissue microarray , ichthyosis vulgaris , epithelium , staining , keratin 5 , basal (medicine) , basal cell carcinoma , basal cell , biology , medicine , atopic dermatitis , immunology , insulin
Background Filaggrin is a protein integral to the structure and function of the epidermis. Filaggrin ( FLG ) loss‐of‐function (LOF) mutations are common and increase the risk of developing atopic dermatitis (AD) and ichthyosis vulgaris (IV). Epidemiologic data suggest a link between skin cancer and AD. We examined if FLG staining pattern can be used to characterize cutaneous squamous cell carcinomas (SCC), basal cell carcinomas (BCC), and reactive squamous epithelium. Methods Tissue microarrays (TMAs) were created from 196 cases of formalin‐fixed paraffin‐embedded (FFPE) SCC and 144 BCC cases. TMAs and sections of reactive squamous epithelium were stained with optimized anti‐FLG antibody and evaluated for FLG expression (normal, abnormal, or negative). Results FLG was absent in poorly differentiated (PD) compared to well‐differentiated (WD) SCC ( P < .0001) and moderately‐differentiated (MD) ( P = .0231) SCC, and in MD compared to WD SCC ( P = .0099). Abnormal staining was significantly increased in PD compared to WD cases ( P = .0039) and in MD compared to WD cases ( P = .0006). Most BCC did not exhibit FLG expression ( P < .05). Reactive squamous epithelium demonstrated normal, but exaggerated FLG expression. Conclusions Our findings demonstrate the differences in FLG expression patterns in types of keratinocyte carcinomas and their mimickers.