Alterations of
caspases, the main executioners of apoptosis, have been described in human
cancers.
Caspase-9 plays a crucial role in the initiation phase of the intrinsic apoptosis pathway.
Caspase-9 is phosphorylated at Thr125 through the
mitogen-activated protein kinase (MAPK) pathway, and this phosphorylation is associated with inhibition of
caspase-9 activation. The aim of this study was to explore whether phosphorylated
caspase-9 (p-caspase-9) expression could be a characteristic of gastric
carcinomas. We analyzed expression of p-caspase-9
protein in 60 gastric
adenocarcinomas by immunohistochemistry using a tissue microarray approach. p-caspase-9 was detected in 33 of the 60
carcinomas (55%). Both early and advanced gastric
carcinomas expressed p-caspase-9. There was no significant association of p-caspase-9 expression with clinocopathological characteristics, including invasion,
metastasis and stage. In contrast to
gastric cancer cells, epithelial cells in normal gastric mucosa showed no or only weak expression of p-caspase-9. Taken together, these results indicate that
caspase-9 is frequently phosphorylated in gastric
carcinomas, and that the phosphorylation of
caspase-9 might be an inhibitory mechanism of caspase-9-mediated apoptosis in gastric
carcinomas. Increased expression of p-caspase-9 in malignant gastric epithelial cells compared to normal mucosal epithelial cells suggests that p-caspase-9 expression might play a role in gastric
carcinoma development.