RET and medullary thyroid gland carcinoma: Given that RET and RAS activate the PI3K/AKT/mTOR pathway, the anti-proliferative activity of everolimus, an inhibitor of mechanistic target of rapamycin (mTOR) approved for the treatment of neuroendocrine tumours and renal cell carcinoma, was demonstrated in an MTC human cell line (Grozinsky-Glasberg et al. 2010) and some activity in a single patient with an MTC (Druce et al. 2012).