[Down-regulation of Caspase-3 expression in precancerous lesions and its relation to gastric carcinogenesis].
OBJECTIVE
To study the level of expression of Caspase-3 protein in precancerous lesions of stomach and its relation to gastric carcinogenesis.


METHODS
Formalin-fixed paraffin embedded tissues from 184 cases of gastric mucosa biopsy and surgically removed specimens, including gastric cancer (GC, N = 20), chronic atrophic gastritis (CAG, N = 6), atrophic gastritis with intestinal metaplasia (IM, N = 31), atrophic gastritis with dysplasia (DYS, N = 114) and normal controls (N = 13) were examined for expression of Caspase-3 protein and Ki-67 index by SABC immunohistochemistry, and for apoptosis by TdT-mediated dUTP biotin nick end labeling (TUNEL) method. Caspase-3, Ki-67 and TUNEL index were compared in different stages of gastric precancerous lesions and their correlation was analyzed.


RESULTS
The positive index of Caspase-3 protein in severe DYS (29.8% +/- 3.9%) showed no significant difference compared with that in GC (26.9% +/- 3.0%, P > 0.05), but was significantly lower than that in low (58.3% +/- 4.2%) and moderate grade DYS (50.4% +/- 4.8%), CAG (68.3% +/- 3.3%) and IM (70.9% +/- 4.3%, P < 0.05). Caspase-3 positive index was significantly correlated with that of apoptosis detected by TUNEL (r = 0.94, P < 0.05). Ki-67 index in Caspase-3 protein positive group (18.3% +/- 2.2%) was significantly lower than that in Caspase-3 negative group (48.9% +/- 3.1%, P < 0.05).


CONCLUSIONS
Caspase-3 protein expression was upregulated in CAG with or without IM and low or moderately low in DYS, while down-regulated in severe DYS and gastric carcinoma, and significantly positively correlated with cell apoptosis. It is suggested that down-regulated expression of Caspase-3 protein somehow contributes to gastric carcinogenesis through an imbalance between cell apoptosis and proliferation.
Yang
Lin
L
No.4 Lab, Cancer Institute, First Affiliatied Hospital, China Medical University, Shenyang 110001, China.
Wu
Dong-ying
DY
Xin
Yan
Y
D000328:Adult; D000368:Aged; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism*; D015536:Down-Regulation; D005260:Female; D005753:Gastric Mucosa / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D005757:Gastritis, Atrophic / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D011230:Precancerous Conditions / Q000201:enzymology* / Q000378:metabolism; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000378:metabolism
D019394:Ki-67 Antigen; D053148:Caspase 3