The genetic and histopathological backgrounds of adrenocortical tumorigenesis remain poorly characterized. In other tissues, there is conclusive evidence that hyperplasia and adenomas precede cancer. In the adrenal, there are few clinical cases of either hyperplasia or adenoma associated with later development of cancer, and there are few biological studies that attempt to characterize this process molecularly. Current research focuses on the early lesions of the adrenal cortex because of their possible molecular link with carcinogenesis, and evidence of their frequent association with atypical forms of Cushing's and Conn's syndromes, obesity, hypertension and/or diabetes. These studies indicate a model for oncogenesis that is the same as that in other tissues. The rarity of adrenal cancer compared to benign lesions could be a clue to unique features of adrenocortical cells. It might also highlight the function of genes that are associated with endocrine tumors in the context of which the concept of gene 'conductors' is introduced here.