Chromogranins derived peptides: from phylogenesis to neuroendocrine tumours

Chromogranins have been characterized in mammals a few decades ago and are routinely used as markers for neuroendocrine tumours. Structural characteri stics of these proteins as well as experimental data suggest that chromogra nins may serve as precursors to biologically active peptides. Recently, the cloning of the cDNAs encoding chromogranins in amphibians and fish reveale d the occurrence of highly conserved regions that are delimited by cleavage sites. These regions give rise to peptides in vivo which may represent the functional determinants of chromogranins. A consent characteristic of chro mogranins in all species is their specific expression in neuroendocrine cel ls. Ln the case of neuroendocrine neoplasia, the detection and the measurem ent of concentrations of chromogranin-derived peptides may improve the diag nosis and the prognosis of some of these tumours.