Cross-talk between NO and HMGB1 in lymphocytic thyroiditis and papillary thyroid cancer.

The controversy on whether or not inflammatory infiltrates in chronic lymphocytic thyroiditis predispose to cancer, has now merged into a debate over the role of the inflammatory infiltrates. The question is how and why some cells become transformed and what factors allow them to spread and in some cases become invasive. Here, we show that the amount of inflammatory mediators such as nitric oxide (NO) and high mobility group Box 1 protein (HMGB1) produced in thyroiditis microenvironment increases in tumors and could be involved in the cellular transformation process. NO and HMGB1 are known to attract macrophages that would promote angiogenesis, matrix remodelling and suppression of an efficient immune response. Inflammatory infiltrates could increase the risk of papillary cancer in patients with autoimmune lymphocytic thyroiditis. Cytokines and soluble inflammatory mediators involved in cancer-related inflammation are not only a target for innovative diagnostic and therapeutic strategies but they also represent a future challenge for oncologists.