High blood levels of chromogranin A point to the presence of slowly progressive gastrointestinal neuroendocrine tumors. Although tentatively used by clinicians, this diagnostic tool lacked reliability because chromogranin A is degraded when released into the circulation. This obstacle has been overcome by the INSERM team headed by Dominique Aunis (U338, Strasbourg) working in cooperation with CIS Bio International. This innovative assay method, which is already commercially available, is the subject of a patent application submitted by CIS Bio international.

A few years ago, Dominique Aunis' team were working on the structure of chromogranin A and found that a fragment of the molecule was protected from protein breakdown. It is the same protected fragment that is measured in the new chromogranin A assay based on radioimmunologic methodology and monoclonal antibodies.

Chromogranin A can now be measured precisely and reliably in peripheral blood. By examining changes in the circulating chromogranin A concentration, clinicians can follow the outcome of gastrointestinal neuroendocrine tumors. Long-term follow-up of these malignancies is important, given that they progress very slowly. The same researcher team are trying to determine if chromogranin A might also serve as a diagnostic marker for other types of neuroendocrine tumor, such as small-cell lung cancer in smokers. If so, this new assay method would find a number of key applications.

For further information :

References
A new human chromogranin A (Cg A) immunoradiometric assay involving monoclonal antibodies against the unprocessed central domaine (145-245)

Degorce F.1, Goumon Y.2, Jacquemart L.1, Vidaud C.1, Bellanger L.1, Pons-Anicet
D.1, Seguin P.1, Metz-Boutigue M.-H.2, Aunis D.2

1CIS bio international, Division In Vitro Technologies, Bagnols-sur-C�ze, France
2INSERM unit 338, Strasbourg, France

British Journal of Cancer, vol 79, issue 1, pp 65-71, 12th december 1998