[504] Keratoacanthoma: A Molecularly Distinct Entity from Squamous Cell Carcinoma

Albert Su, Seong Ra, Xinmin Li, Rajan Kulkarni, Scott Binder. UCLA Medical Center, Los Angeles, CA; San Diego Pathologists Medical Group, San Diego, CA

Background: Keratoacanthomas (KA) are crateriform squamous lesions that grow rapidly then involute in the sun exposed skin of elderly fair skinned patients. KA is a controversial entity with some believing that it represents a variant of squamous cell carcinoma (SCC), while others believe it is a distinct benign self-limited squamoproliferative lesion. Our objective was to examine the molecular relationship of KA to SCC utilizing DNA microarray technologies.
Design: DNA microarray studies were performed on formalin-fixed and paraffin-embedded blocks of skin: Ten cases of SCC arising from actinic damage and ten cases of KA utilizing the AffymetrixU133plus2.0 array.
Results: Keratoacanthoma demonstrated 1449 differentially expressed genes in comparison with SCC (>5 fold change: p<0.001) with 908 genes upregulated and 541 genes downregulated. The most significantly upregulated genes include CDR1, MALAT1, TPM4, CALM1, and TMED2. The most significantly downregulated genes include LOC441461, TYRP1, CEL, INTS6, and WWOX. Functional analysis comparing KA to normal skin suggests that cellular development, cellular growth and proliferation, cell death, and cell cycle pathways are involved in the pathogenesis of KA.
Conclusions: KA should be classified as a distinct entity separate from SCC based upon its unique molecular profile and clinicopathologic characteristics.
Category: Dermatopathology

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 70, Monday Morning


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