Neuroendocrine tumors (NETs) are neoplasms that arise from cells of the endocrine (hormonal) and nervous systems. Many are benign, while some are malignant. They most commonly occur in the intestine, where they are often called “carcinoid tumors”, but they are also found in the pancreas, lung and the rest of the body.
Although there are many kinds of NETs, they are treated as a group of tissue because the cells of these neoplasms share common features, such as looking similar, having special secretory granules, and often producing biogenic amines and polypeptide hormones
This mode-of-action animation film deals with neuroendocrine (or islet cell) tumors. It describes how cancerous neuroendocrine tumors — or NET for short — develop from islet cells in the gastrointestinal tract and the pancreas. At the time of diagnosis, half of the patients affected by islet cell cancer are already in an advanced stage. All types of tumors or neoplasms – including NET — show an uncontrolled, invasive growth caused by abnormal proliferation, disrupted apoptosis and increased angiogenesis.
On the molecular level, the mode-of-action animations show how pathological changes that later result in islet cell tumors or neoplasms are mediated via different signalling pathways, with the multi-functional kinase mTOR playing a central role. The beginning of these signalling pathways is constituted by membrane-bound growth factor receptors. Activation of the receptors causes the formation of certain patterns, which recruit intracellular molecules to the membrane and activate them.
The resulting signal is then transmitted via phosphorylations. Some of these lead directly to the activation of proteins, others effect the dissociation of an inhibitory complex, thus releasing active proteins.
These in turn activate the highly conserved kinase mTor — a central mediator of many signalling pathways.