Brain metastasis from EGFR-mutated non-small cell lung cancer: Secretion of IL11 from astrocytes up-regulates PDL1, increases apoptosis of T lymphocytes, and promotes immune escape.

To investigatethe mechanism responsible for the astrocyte-induced upregulation of PDL1 in BM cells, we constructed the tumor cell-astrocyte co-culture system. We then performed gene expression profiling analysis using data obtained from RNA-seq of cells co-cultured compaired with single cells. Comparative gene expression profiling analysis of RNA-seq data for astrocytes co-cultured with PC9-BrM3 cells and single astrocytes or PC9-BrM3 cells co-cultured with astrocytes and single PC9-BrM3 cells.