294 Abnormal collagen I structure and protein expression in desmoplastic cutaneous squamous cell carcinoma

Desmoplasia is a highly aggressive histopathologic feature of cutaneous squamous cell carcinoma CSCC independently associated with death from CSCC. It the deposition abnormal collagen around tumor as seen on H&E. However, structure this unknown. Herein, early immunofluorescence (IF) studies to define differences between normal and desmoplastic structures are reported. Tumor samples 27 patients were graded for desmoplasia using semi-quantitative grading scale. Samples prominent versus no analyzed bulk RNA-seq analysis by Nanostring technology. Additionally, 7 skin multispectral IF. K14 identified keratinocytes, vimentin (VIM) fibroblasts. COL1A1 was significantly upregulated gene in CSCC, compared non-desmoplasia (Log2FC=2, p<0.001). COL1 IF intensity decreased stroma (p<0.0001) (p<0.0001). The staining pattern showed markedly altered I comprised thin, wispy strands, keeping H & E appearance collagen. Surprisingly, increased (keratinocyte) regions CSCCs non-desmoplastic epidermis (P<0.0001). degeneration present some cells. This COL1-positive phenotype number cells/mm2compared (413 vs 1101, p<0.0001). These findings indicate that expression quantifiably structurally different native collagens. Desmoplastic keratinocytes may produce form