title: Bcl-2 expression and allelic loss of the p53 gene in gastric carcinomas.
abstract: In order to clarify the association between bcl-2 protein (Bcl-2) expression and genetic alteration, we investigated p53 and DCC (deleted in the colon carcinoma gene locus) gene abnormalities in Bcl-2-positive and -negative gastric carcinomas using a polymerase chain reaction/loss of heterozygosity (LOH) assay. Bcl-2 immunoreactivity was found in 25 of 178 (14%) gastric carcinoma cases. With these 25 positive cases, the proportion 18/87 (20.6%) of the total in early stages demonstrating invasion of the mucosa and/or submucosa was significantly greater (P = 0.013) than the 7/91 (7.7%) found for advanced tumors exhibiting invasion into or through the muscularis propria. However, there was no statistically significant variation between the proportions for differentiated (17/98 cases, 17.3%) and undifferentiated (8/80 cases, 10%) lesions. Sixteen Bcl-2-positive cases (9 cases were not studied because of insufficient specimen material to allow extraction of DNA) and 31 cases randomly selected from a Bcl-2-negative group were analyzed for the presence of p53-LOH or DCC-LOH and for p53 by immuno-histochemistry. The minority of the Bcl-2-positive group had p53-LOH and were immunopositive for p53 (P = 0.033, P = 0.028 respectively), while no association was found in the Bcl-2-negative category. In contrast, there was no correlation at all between Bcl-2 expression and DCC-LOH although the number of informative cases analyzed was too small to allow definite conclusions. These results indicate that Bcl-2 may be predominantly expressed at an early stage in gastric carcinomas, possibly in negative association with p53 gene abnormalities.
authors.affiliation: Department of Pathology, Kitasato University, School of Medicine, Kanagawa, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Saegusa
authors.forename: Y
authors.initials: Y
authors.lastname: Takano
authors.forename: Y
authors.initials: Y
authors.lastname: Kamata
authors.forename: J
authors.initials: J
authors.lastname: Okayasu
mesh_terms: D000483:Alleles; D001483:Base Sequence; D002467:Cell Nucleus / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D017353:Gene Deletion; D015870:Gene Expression; D016163:Genes, DCC; D016158:Genes, p53; D006579:Heterozygote; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000096:biosynthesis*; D019253:Proto-Oncogene Proteins c-bcl-2; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism*
chemical_list: D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2