RET and neoplasm: Although the role of RET in cancer has not been directly investigated, it is now clear that oxygen tension in the tumour microenvironment is subjected to ample temporal and spatial fluctuations as a result of the chaotic organisation of the neoangiogenic process.112 The resulting imbalance between oxygen supply and demand suggests that the tumour tissue is constantly subjected to recurrent ischaemia/reperfusion cycles in which RET might play a major role in altering ROS homoeostasis.