Background: The possible association between neuroendocrine pattern and cancer prognosis could have substantial clinical implications, but the studies performed have generated conflicting results. As chromogranin-A (CGA) and dense-core granules are expressed concordantly, CGA expression may be used as a marker for cells expressing the complete neuroendocrine cell phenotype.
Materials and methods: Fifty-six patients with primary colon carcinoma who underwent potentially curative surgery were analyzed. For immunohistochemical study a monoclonal antibody specific for human chromogranin A was used. The tumor was considered positive when the number of CGA cells was higher than 10% in the section. The relation between CGA-positivity and depth of parietal invasion, lymph-node status and differentiation grade was examined.
Results: We observed positive immunostaining in 22 cases out of 56 (39.3%). Significant association was found between CGA-positivity and lymph-node metastasis.
Conclusion: CGA overexpression could reflect a more aggressive tumor. If our results are confirmed, we should consider the CGA + colon cancer patients at risk for lymph-node disease and therefore include them in a adjuvant chemotherapeutic protocol.