Aiming to immune elimination of ovarian cancer stem cells

Figure 5 Dysfunctional immune system in peritoneal cavity of patients with ovarian cancer. Many types of immune cells are recruited to the ovarian tumor site, including regulatory T cells (Treg), dendritic cells (DC), tissue associated macrophages (TAM) myeloid derived suppressor cells (MDSC)[155], plasmacytoid DCs (pDC), natural killer cells and T cells (CD4, CD8). Once being recruited, most cells function abnormally and become immune suppressive. T cells specific for Oct4 (αOct4 T cell), CD4⁺ T cells, CD8⁺ T cells are damaged, due to dysfunctional DCs, pDCs and suppressive Tregs. Also the secretion of immune suppressive cytokines and lipid metabolites contribute to establish such an immunosuppressive tumor microenvironment, and may also be required for cancer stem cells (CSCs) maintenance. So even if the CSC is recognized, T cells lack the ability to eliminate it. Whereas such suppression mechanisms are not operative in the peripheral blood of the patients, once the CSC migrates to the peripheral, it is killed.