Abstract PO063: Transcriptomic analysis identifies changes in gene expression in Actinic Keratoses after treatment with imiquimod and differential gene expression

Abstract

Background: The presence of actinic keratoses (AKs) increases a patient’s risk of developing squamous cell carcinoma (SCC) by greater than six-fold. It is difficult to predict which AKs will progress to become SCC, and topical treatments such as imiquimod are used to treat the entire affected field indiscriminately, effectively eliminating AKs in 50% of patients but sometimes resulting in severe inflammation and pain. Defining biomarkers to predict response to treatment would be helpful to guide therapy. Objectives: To evaluate the effect of imiquimod on the tumor microenvironment by measuring transcriptomic differences in AKs before and after treatment in patients treated with imiquimod. Methods: Biopsies were collected prospectively from 21 patients with presumptive AK and examined histologically. All patients were treated with imiquimod 3.75% on a short cyclical treatment regimen. 19 patients had available pre-treatment AK biopsies and 14 patients had paired pre- and post-treatment biopsies. RNA was extracted and transcriptomic analyses of 788 genes were performed using the nanoString assay. Results: Imiquimod significantly decreased total number of AKs by study endpoint at week 14 (pCitation Format: Megan H. Trager, Emanuelle Rizk, Sharon Rose, Branden Lau, Ben Fullerton, Kuixi Zhu, Jaya Pradhan, Michael Moore, Ayush Chandra, Margaret Bogardus, Giselle Singer, Robyn Gartrell-Corrado, Rui Chang, Larisa Geskin, Yvonne Saenger, Gary Goldenbery. Transcriptomic analysis identifies changes in gene expression in Actinic Keratoses after treatment with imiquimod and differential gene expression [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2020 Oct 19-20. Philadelphia (PA): AACR; Cancer Immunol Res 2021;9(2 Suppl):Abstract nr PO063.