Programmed death-ligand 1 (PD-L1) is a transmembrane protein that binds to the inhibitory receptor programmed death 1 receptor (PD-1), causing a down regulation of immune responses. PD-L1 is typically expressed on normal cells but has been observed in immune cells and tumor cells, see [1]. while PD-1 is typically expressed on cytotoxic T-cells and other immune cells. Tumor cells can upregulate PD-L1 expression and avoid being attacked by the body’s immune system, making an interruption of the PD-1/PD-L1 interaction an attractive method for assisting the immune system in destroying tumor cells, see [2].
SOX10 is a nuclear transcription factor that has been shown to be a sensitive and specific marker for malignant melanoma, see [3]. Combining SOX10 and PD-L1 enables the user to assess whether PD-L1 expression originates from tumor cells or adjacent non-tumor cells.
This APP can be used to determine the number of tumor and non-tumor cells that express PD-L1 without having to outline tumor regions.