Monocytes promote UV‐induced epidermal carcinogenesis

Mononuclear phagocytes consisting of monocytes, macrophages, and DCs play a complex role in tumor development by either promoting or restricting growth. Cutaneous squamous cell carcinoma (cSCC) is the second most common nonmelanoma skin cancer arising from transformed epidermal keratinocytes. While present at high numbers, tumor-infiltrating resident myeloid cells formation cSCC largely unknown. Using transgenic mice depleting antibodies to eliminate specific types skin, we investigated involvement mononuclear UV-induced K14-HPV8-E6 mice. Although Langerhans were enriched tumor, their contribution was negligible. Equally, dermal macrophages dispensable for cSCC. In contrast, lacking circulating monocytes completely resistant cSCC, indicating that promote development. Collectively, these results demonstrate critical classical initiation cancer.