Bcl-2 expression and its association with cell kinetics in human gastric carcinomas and intestinal metaplasia.
The bcl-2 protooncogene was initially discovered at the t(14;18) chromosomal breakpoint in follicular lymphomas. It has been demonstrated that bcl-2 protein (Bcl-2) expression blocks apoptosis and plays an important role in cell development and maturation. In the present study, Bcl-2 expression was immunohistochemically examined in 103 cases of gastric carcinoma, as well as 64 cases of non-carcinous gastric mucosa, and its correlation with apoptosis, cell proliferation and p53 immunoreactivity was investigated. Bcl-2 was detected in 18.0% of differentiated-type gastric carcinomas (9 of 50) and 7.5% of the undifferentiated type (4 of 53). In adjacent intestinal metaplastic gastric epithelium, the incidence of Bcl-2 positivity in the incomplete type (21/23, 91.3%) was significantly higher than in the complete type (23/41, 56.1%) (P < 0.04). Double immunostaining for Bcl-2 and Ki-67 clearly revealed the majority of Bcl-2-positive cancer cells to be in a nonproliferating state, although some cancer cells expressed both proteins together. Statistical assessment demonstrated that the average Ki-67 labeling index and apoptotic labeling index in Bcl-2-positive foci were significantly lower than in Bcl-2-negative foci (P < 0.0001, P < 0.0003). In addition, a significant dissociation between Bcl-2 and p53 immunoreactivity was found in cancer tissues. These results indicate that aberrant Bcl-2 expression in gastric carcinomas possibly originates from intestinal metaplastic epithelium, and suggest a possible role in tumor development and growth.
Saegusa
M
M
Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan.
Takano
Y
Y
Okayasu
I
I
D000230:Adenocarcinoma / Q000737:chemistry; D017209:Apoptosis; D002277:Carcinoma / Q000737:chemistry* / Q000556:secondary; D018279:Carcinoma, Signet Ring Cell / Q000737:chemistry; D002455:Cell Division; D002465:Cell Movement; D005753:Gastric Mucosa / Q000737:chemistry / Q000166:cytology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007124:Immunoenzyme Techniques; D007414:Intestinal Neoplasms / Q000737:chemistry* / Q000556:secondary; D015513:Oncogene Proteins / Q000032:analysis*; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D015513:Oncogene Proteins; D016159:Tumor Suppressor Protein p53