A number of studies point to an aberrant differentiation and accumulation of CD14+ PD-L1+ M2-macrophage-like cells in the microenvironment of cervical cancer, which promote immunosuppressive conditions and are associated with tumor invasion, angiogenesis and metastasis. Therapeutic targeting of these macrophages may tip the balance in favor of antitumor immunity. Cervical cancer is the fourth most common cancer among women worldwide and is caused by a persistent infection and subsequent integration of high-risk types of the human papillomavirus. Continuous expression of the viral oncoproteins E6 and E7 has been shown essential to maintain the transformed state of infected keratinocytes. As these non-self oncoproteins are immunogenic, cervical cancer requires a highly immune suppressed tumor microenvironment to metastasize through lymphovascular space invasion (LVSI) to the pelvic tumor-draining lymph nodes (TDLN). Unraveling the mechanisms underlying this immune suppression may uncover novel therapeutic targets aimed at loco-regional control of cervical cancer.
Keywords: COX, cyclooxygenase; DC, dendritic cell; IL, interleukin; LVSI, lymphovascular space invasion; MDSC, myeloid-derived suppressor cells; PD-L1; PD-L1, programmed death-ligand 1; PGE2, prostaglandin-E2; TDLN, tumor-draining lymph node; Treg, regulatory T cell; cervical cancer; dendritic cells; immunotherapy; macrophages; tumor microenvironment; tumor-draining lymph nodes.