299 Biomarkers of early UV-induced skin cancer

Actinic keratosis (AK) and squamous cell carcinomain situ (SCCIS) are the most common precancerous lesions may progress to cutaneous carcinoma (cSCC), second cancer in US. Biomarker identification associated with keratinocyte clones undergoing UV-induced selection provide new targets treat AK/SCCIS. Prior studies using comparative whole exome-seq RNA-seq of SCCIS epidermis identified UV-signature loss-of-function mutations NOTCH1-3 that represent AK/SCCIS precursors upregulation calcium signaling genes SCCIS. To identify cooperate loss NOTCH function during clonal selection, we performed spatial transcriptomics on Notch-deficient UV-irradiated K14-CreER;ROSA26-loxp-STOP-loxp-tTA;TRE-H2BGFP;TRE-DNMAML transgenic mice which permit visualization epidermal keratinocytes. Mice harboring scattered keratinocytes skin were followed by vivo macrofluorescence microscopy track clone development. Representative samples irradiated containing subjected transcriptomic analysis qRT-PCR RNAscope. Spatial 26 differentially expressed (FDR<1x10-5), including calmodulin isoform CALM3 (p<4.6x10-6). RNAscope hybridization semi-quantitative scoring (range 0-4, 4 is strong signal) showed overexpression (Score 4>) compared 1). CALM1 CALM2 also overexpressed 3) High resolution human confirmed increased (FDR<0.003) (FDR<1x10-5) expression (N=34). These data indicate pathways regulated upregulated