Tumor microenvironment: The culprit for ovarian cancer metastasis?

Despite chemotherapy and surgical debulking options, ovarian cancer recurs and disseminates frequently, with poor prognosis. However, the molecular mechanisms underlying ovarian cancer metastasis still remain unelucidated. The tumor microenvironment, consisting of stromal cells (including fibroblasts, macrophages, regulatory T cells, myeloid-derived suppressor cells, endothelial cells, pericytes and platelets), the extracellular matrix component (EMC) (including inflammatory cytokines, chemokines, matrix metalloproteinases, integrins, and other secreted molecules) and exosomes (small extracellular vesicles loaded with molecules), establishes an autocrine-paracrine communication circuit that reinforces invasion and cancer cell metastasis via reciprocal signaling. Recent evidences have unraveled the significant contribution of tumor microenvironment to ovarian cancer metastasis. In this review, we provide a comprehensive landscape of the reciprocity between tumor stroma and ovarian cancer cells upon metastasis, aiming to offer novel clues on the development of novel diagnostic biomarkers and therapeutic targets for ovarian cancer in future clinical practice.