Methodological aspects and clinical value of chromogranin A assessment

Since the development of the first immunoassay for circulating chromogranin A in 1984, numbers of studies have been carried out to evaluate its clinical interest. Initially considered as a tumour marker for pheochromocytoma, Chromogranin A clinical value has been rapidly? extended to most of the neuroendocrine tumours, sometimes in combination with other eutopic or ectopic secretions. These studies hare also contributed to the methodological evolution of Chromogranin A assessment. First improvements were made possible by the generation of specific monoclonal antibodies anti-Chromogranin A, followed by the development of two-sito immunometric assays. The aim of this review is to summarise the clinical status of Chromogranin X: particularly in terms of specificity and sensitivity for neuroendocrine tumours, and in comparison to other well-established clinical analytes. The methodological criteria related to the specificity of immunodetecting reagents for Chromogranin A and its degradation products, as well as the improvements brought to these analytical tools are also discussed in this review.