1022P Frequency of PD1-negative and PD-1-positive ILCs in breast cancer patients depending on PD-L1 status

The tumor microenvironment plays a key role in the development and progression of breast cancer. Immune checkpoint inhibitors for the PD-1/PD-L1 pathway activate the immune cells of the tumor microenvironment. Current knowledge suggests that the effectiveness of therapy depends on the ratio of the types of TH1 and TH2 immune cells in the tumor microenvironment. TH1 type of immune cells is associated with a favorable prognosis, and the TH2 type of immune cells with a poor prognosis. Innate lymphoid cells (ILCs) are analog of T-helper lymphocytes and remain one of the least studied groups of immune cells.