In the last few years, molecular targeted therapies have replaced traditional cytotoxic chemotherapy in the fight against many cancers to the extent that our understanding of tumor biology has become more sophisticated. This shift has markedly changed adverse event profiles, compared to cytotoxic chemotherapy, affecting a diverse range of organ systems. Everolimus was approved by the FDA in 2011 for the treatment of progressive pancreatic NE tumors. It is an inhibitor of mammalian target of rapamycin (mTOR) and exhibits antitumor activity via disruption of various signaling pathways and it's used in the treatment of advanced renal cell cancer, breast cancer and neuroendocrine tumors (NET); it’s used also as anti-rejection agent for transplantation but with lower doses for anti-rejection (1.5–3.0 mg/day) than for anti-cancer (5–10 mg/day) treatment. Metabolic side effects are the most frequent reported and will be discussed in this review.
