RET and neuroendocrine neoplasm: Germ line gain-of-function RET mutations are associated with familial neuroendocrine tumours and medullary thyroid cancers; RET mutations are also found in sporadic medullary and papillary thyroid carcinoma (Ichihara et al, 2004; Morandi et al, 2011; Sariola and Saarma, 2003).