Chromogranin A(CgA) appears to be a major secretory protein in the parathyroid secretory granules and its distribution serves as a marker for neuroendocrine lineage differentiation. The amino acid sequence of bovin CgA shows a high degree of homology to pancreastatin, an isolated porcine peptide that inhibits glucose-induced insulin secretion. Three stomach and seven colon carcinoma cell lines established from Korean patients were used in this study. We tried to classify these cell lines into neuroendocrine lineage by detecting the expression of CgA mRNA. According to the results of Northern blot, the levels of CgA mRNA were highly elevated in two colorectal carcinoma cell lines such as SNU-61 and SNU-C4. To detect whether CgA mRNA expression was due to gene amplification or gene rearrangement, Southern blot analysis was performed. One major band was detected in all cell lines, however, CgA mRNA in SNU-61 and SNU-C4 was not amplified as compared to the other cell lines. From the above result, we concluded that the elevation of CgA mRNA expression was not due to gene amplification or gene rearrangement, hence, its expression might be transcriptionally or post-transcriptionally increased.