IGF1 and gastrointestinal stromal tumor: Subjects with acromegaly, which is due to excessive GH secretion, have elevated levels of serum IGF-1 and are well-recognized to be at increased risk of colorectal cancer, with possible association also with breast, thyroid and prostate cancers and a recent report of multiple additional tumors including cancers of the lung, kidney, adrenal and GIST [74,75].