ENPP2 and melanoma: Several extracellular, mainly pro-inflammatory, factors have been suggested to stimulate ENPP2/Enpp2 expression, many through the transcription factors indicated above: TNF in synovial fibroblasts, hepatocytes, hepatoma cell lines, and thyroid cancer cells (32–35), IL-1β in thyroid cancer cells (34), IL-6 in dermal fibroblasts (36), as well as galectin 3 in melanoma cells (27).