Dr. Jekyll and Mr. Hyde: MAP17’s up-regulation, a crosspoint in cancer and inflammatory diseases

Inflammation is a common defensive response that is activated after different harmful stimuli. This chronic, or pathological, inflammation is also one of the causes of neoplastic transformation and cancer development. MAP17 is a small protein localized to membranes with a restricted pattern of expression in adult tissues. However, its expression is common in destabilized cells, as it is overexpressed both in inflammatory diseases and in cancer. MAP17 is overexpressed in most, if not all, carcinomas and in many tumors of mesenchymal origin, and correlates with higher grade and poorly differentiated tumors. This overexpression drives deep changes in cell homeostasis including increased oxidative stress, deregulation of signaling pathways and increased growth rates. Importantly, MAP17 is associated in tumors with inflammatory cells infiltration, not only in cancer but in various inflammatory diseases such as Barret’s esophagus, lupus, Crohn’s, psoriasis and COPD. Furthermore, MAP17 also modifies the expression of genes connected to inflammation, showing a clear induction of the inflammatory profile. Since MAP17 appears highly correlated with the infiltration of inflammatory cells in cancer, is MAP17 overexpression an important cellular event connecting tumorigenesis and inflammation?