Chromogranin-A expression in gastric and colon cancer tissues.
We studied the expression of chromogranin A (CgA) in human gastric (n = 17) and colorectal (n = 18) adenocarcinomas by nucleic acid hybridization and immunohistochemical analyses using a specific monoclonal antibody (MAb) to human chromogranin A (CgA). Some corresponding adjacent non-malignant mucosal tissues were also examined.


RESULTS
(1) Northern blotting: of 3 normal gastric mucosas examined, 2 (67%) had an easily detected signal for expression of CgA. Only one of 14 gastric carcinomas (7%) and one of 18 colorectal carcinomas (6%) had easily detected RNA signals. (2) Immunohistochemical staining: all non-malignant samples of gastric and colonic mucosa contained CgA-positive neuroendocrine (NE) cells. Two of 17 (12%) gastric adenocarcinomas, and 3 of 18 (17%) of colorectal adenocarcinomas contained CgA-positive tumor cells. Interestingly, the positive cases detected by immunohistochemistry included both cases detected by Northern blotting. Of the 5 cases detected by immunohistochemistry, 2 gastric cancers and 1 rectal carcinoma contained many diffusely scattered positive cells, occurring singly or in small clusters, while 2 colorectal carcinomas contained only occasional single CgA-positive tumor cells. In one of the positive gastric cases, a well-differentiated adenocarcinoma arising in a tubular adenoma, both the adenomatous and the carcinomatous elements contained positively staining cells. Our specific assays for CgA indicate that (1) a NE cell component, either diffusely scattered or occasional, occurs in about 15% of gastric and colorectal tumors; (2) there is no correlation between the presence of NE cells and degree of tumor differentiation; and (3) because only a minority of the tumor cells in positive cases stain for CgA, immunohistochemistry is a more sensitive method than Northern blotting.
Laboratory of Tumor Cell Biology, Seoul National University College of Medicine, Korea.
J G
JG
Park
G Y
GY
Choe
L J
LJ
Helman
A F
AF
Gazdar
H K
HK
Yang
J P
JP
Kim
S H
SH
Park
Y I
YI
Kim
D001078:APUD Cells / Q000473:pathology; D000230:Adenocarcinoma / Q000737:chemistry* / Q000473:pathology; D000328:Adult; D000368:Aged; D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis*; D003110:Colonic Neoplasms / Q000737:chemistry* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000737:chemistry* / Q000473:pathology; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000473:pathology
C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins