IGFBP2 and lung cancer: In 2006, Sato and collaborators, by studying dedifferentiated lung cancer cells, suggested that the structure of the human IGFBP2 promoter can be organized into three elements, represented as the distal (localized between −674 and −314, which apparently acts as an enhancer element), middle (extends from −314 to −134, and seems to be an inhibitor/silencer), and proximal regulatory element (extends from −134 to the transcription start site, and apparently acts as a regulator of transcriptional activity).