047 Pro-dysfunction and weak anti-cancer tumor infiltrating lymphocytes associated with more aggressive BCC subtype

Background: Immune response is key in defense against basal cell carcinoma (BCC). We aim to better define the immune tumor microenvironment this cancer. Methods: CD8+ infiltrating lymphocytes (TILs) obtained from fresh BCC specimens nodular subtype (“nBCC”, n=6) versus infiltrative (“iBCC”, were subject single-cell RNA profiling. Data analyzed using iCellR. Results: TILs clustered based on gene expression as follows: cytotoxic (GZMA, GZMB, IFN-γ, PRF1); naïve (CCR7, LEF1, TCF7, IL7R, OX40); exhausted (BTLA, CTLA4, PDCD1, TIM3, LAG3, STAT3, 4-1BB); and regulatory (FOXP3, additional subtypes observed for naïve, exhausted, T cells. A significantly greater percentage of lesser iBCC compared nBCC. Further analysis revealed a unique, pro-tumor-controlling nBCC highly suppressive iBCC; moreover, exclusively low activity subtype. Additionally, all was not different across subtype; however, there proportion progenitor terminally Conclusion: Two proportions pro-tumor controlling one lower identified iBCC, possibly contributing relative aggressiveness these tumors. more tended cluster phenotype that may be responsive checkpoint blockade therapy.