At the biochemical level, this may be attributable to markers associated with hormonal activity, such as chromogranin A, hydroxy indole acetic acid, and—in the specific case of von Hippel Lindau syndrome—vasointestinal peptide and polypancreatic peptide, for which a positive correlation SRE-TV has been shown [86,97]. Here, CHGA is linked to von Hippel-Lindau disease.