Tumor-associated macrophages (TAMs) constitute the main population of immune cells present in the ovarian tumor microenvironment. These cells are characterized by high plasticity and can be easily polarized by colony-stimulating factor-1, which is released by tumor cells, into an immunosuppressive M2-like phenotype. These cells are strongly implicated in both the progression and chemoresistance of ovarian cancer. The main pro-tumoral function of M2-like TAMs is the secretion of a variety of cytokines, chemokines, enzymes and exosomes that reach microRNAs, directly inducing the invasion potential and chemoresistance of ovarian cancer cells by triggering their pro-survival signaling pathways. The M2-like TAMs are also important players in the metastasis of ovarian cancer cells in the peritoneum through their assistance in spheroid formation and attachment of cancer cells to the metastatic area—the omentum. Moreover, TAMs interplay with other immune cells, such as lymphocytes, natural killer cells, and dendritic cells, to inhibit their responsiveness, resulting in the development of immunosuppression. The detrimental character of the M2-like type of TAMs in ovarian tumors has been confirmed by a number of studies, demonstrating the positive correlation between their high level in tumors and low overall survival of patients.

High-dose intravenous N-acetylcysteine reduces oxidative stress. However, it does not provide an additional clinical benefit to placebo with respect to CIN and myocardial reperfusion injury in nonselected patients undergoing angioplasty with moderate doses of contrast medium and optimal hydration. (Myocardial Salvage and Contrast Dye Induced Nephropathy Reduction by N-Acetylcysteine [LIPSIA-N-ACC]; NCT00463749).

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In cancer, numerous cells of both innate and adaptive immune systems are activated. Polymorphonuclear neutrophils are potent effector cells of inflammation that are an important component of tumour development and progression. The important signalling proteins that are involved in neutrophil functions are extracellular signal‐regulated kinases 1/2 (ERK1/2). We investigated the reactive oxygen species (ROS) production, adhesive ability and CD11b/CD18 adhesion molecule expression on neutrophils isolated from peripheral blood of ovarian cancer patients and the in vitro response of these cells to stimuli and direct contact with ovarian cancer cells isolated from tumour. We found that functional activities of neutrophils isolated from patients with advanced stages of ovarian cancer (FIGO III/IV) were intensified in comparison to neutrophils isolated from healthy female volunteers. Neutrophils of cancer patients produce higher amounts of ROS in response to stimuli than those of control group. Unstimulated neutrophils of patients possess higher expression of CD11b/CD18 molecule that is accompanied by increased adhesive ability of these cells. Our results reveal that augmented functional activities of neutrophils may result from the intensification of ERK1/2 kinases phosphorylation. We found that interactions with ovarian cancer cells modulate neutrophil functions as a result of cell‐to‐cell direct contact. We conclude that ovarian cancer cells affect pro‐inflammatory activities in neutrophils via influence of signalling pathways in response to stimuli. Our results suggest the possibility that neutrophils responding to contact with cancer cells contribute to the progression and metastatic potential of tumour cells.

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