Medullary thyroid carcinoma (33%) and pheochromocytoma (19%) are the most prevalent among the cases of isolated ectopic-CRH, while carcinoid (5%) and small cell lung carcinoma (9.5%) are less common, different from ectopic ACTH cases, with the latter two as the most prevalent causes (Table 2)[7-17]. This evidence concerns the gene CRH and small cell lung carcinoma.