The role of selected molecular factors in ovarian cancer metastasis.

The main reason for treatment failure in ovarian cancer is chemoresistance and the presence of metastasis. Ascites, whichallows the physical movement of cancer cells, the lymphovascular pathway, and several molecular factors and signalling axes, are involved in metastasis. Ascites, with the involvement of cytokines and chemokines, MAPK/STAT1 and NOTCH as well as CXCL12/CXCR4 signaling pathways and circulating anoikis induces cancer dissemination, in particular to the peritoneum and omentum. The spread of lymphatic and bloodstream cancer cells is a multi-stage process. Tumour infiltration of the stroma and lymphovascular space (LVSI) produces biologically active cancer-associated fibroblasts and macrophages (CAFs, TAMs) that secrete numerous cytokines, chemokines and growth factors, inhibit NK function, induce epithelial-mesenchymal transition (EMT), resulting in an increase of the metastatic potential of cancer cells and the formation of cancer stem cells (CSCs). Overexpression of some genes, and microRNAs, in LVSI-(LMGS) associated with metastasis has been identified. The role of extracellular vesicles (EVs) transporting metastasis-associated factors has been described as has the role of cancer stem cells (CSCs) in chemotherapy resistance and metastasis. Sirtuins, enzymes involved in metastasis formation, have also been detected. Certain types of microRNAs (miR-509-3p, microRNA-506-3p) and melatonin have been shown to inhibit metastasis.