Mucin phenotype and background mucosa of intramucosal differentiated-type adenocarcinoma of the stomach.
OBJECTIVE
Gastric carcinomas have been divided into differentiated (intestinal) and undifferentiated (diffuse) types. Recently, classification studies based on mucin expression have revealed that some differentiated-type carcinomas are of a gastric phenotype. In this study, we investigated the clinicopathological features of differentiated-type adenocarcinomas and evaluated the background mucosa of the stomach based on mucin expression by the tumors.


METHODS
Seventy-six intramucosal differentiated-type adenocarcinomas of the stomach were evaluated macroscopically and histologically. The mucin expression of tumor cells was examined by immunohistochemical staining with monoclonal antibodies against human gastric mucin (45M1), class III mucin (HIK1083), small intestinal mucinous antigen (SIMA-4D3), and MUC2 (Ccp58). Tumors were classified by phenotype as gastric (G-type), intestinal (I-type), mixed (M-type), or null (N-type). Not only the clinicopathological features but also the background mucosa of the stomach of G-type and I-type carcinomas were compared histologically and serologically.


RESULTS
Seventeen tumors (22.4%) were classified as G-type, 31 (40.8%) as I-type, 22 (28.9%) as M-type, and 6 (7.9%) as N-type. The frequencies of elevated type tumors and papillary adenocarcinomas and the ratio of moderately/well-differentiated adenocarcinomas were higher in G-type than in I-type carcinomas. The scores for glandular atrophy and intestinal metaplasia were higher and the scores for chronic inflammation, polymorphonuclear neutrophil activity, and the density of Helicobacter pylori were lower in G-type than in I-type tumors. The serum level of pepsinogen I and the pepsinogen I/II ratio were significantly lower in G-type than in I-type tumors.


CONCLUSIONS
G-type carcinoma is the predominant phenotype of papillary adenocarcinoma. The background mucosa of G-type carcinoma is associated with glandular atrophy and intestinal metaplasia, whereas that of I-type carcinoma is associated with active and chronic inflammation induced by H. pylori infection.
Department of Medicine and Molecular Science, Graduate School of Biomedical Sciences, Hiroshima University Hospital, Hiroshima, Japan.
Atsunori
A
Sasaki
Yasuhiko
Y
Kitadai
Masanori
M
Ito
Shinji
S
Tanaka
Masaharu
M
Yoshihara
Ken
K
Haruma
Kazuaki
K
Chayama
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000368:Aged; D014408:Biomarkers, Tumor; D005260:Female; D005752:Gastric Mucins / Q000145:classification / Q000378:metabolism; D005753:Gastric Mucosa / Q000473:pathology; D005756:Gastritis / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009077:Mucins / Q000145:classification*; D010641:Phenotype; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology
D014408:Biomarkers, Tumor; D005752:Gastric Mucins; D009077:Mucins