Apoptosis and Fas-ligand expression correlate to the histopathological grade of gastric smooth muscle tumors.
BACKGROUND
Apoptosis is associated with the tumor grade in various types of carcinomas or lymphomas, but less is understood about the association of apoptosis in mesenchymal tumors. In the prior studies, expression of apoptotic regulatory proteins, Bcl-2, Fas and its ligand, Fas-ligand, has been related to apoptotic index (AI) and histopathological grade of tumors. Our study investigated the incidence of apoptosis in gastric smooth muscle tumor and the correlation of the apoptotic index (AI) with the histopathological grade of the tumors. We evaluated the relationship of apoptotic regulatory proteins to the AI and tumor grade.


METHODS
Using immunohistochemistry and the terminal deoxynucleotidyl transferase (TdT)-mediated digoxigenin-dUTP nick end-labeling (TUNEL) assay, we analyzed the expression of Bcl-2, Fas, Fas-ligand, and AI in 26 cases of gastric smooth muscle tumors.


RESULTS
The incidence of greater than 10 apoptotic cells per 10 high-power fields (HPFs) was 73% (19/26 cases). The AI was significantly associated with malignant tumors (P = 0.006) and mitotic counts (P = 0.006) but not with tumor size. Bcl-2, Fas, and Fas-ligand were detected in 13 (50%), 14 (53.8%), and 19 (73%) cases, respectively. Interestingly, Fas-ligand was significantly correlated to malignancy (P = 0.006), mitotic counts (P = 0.006), and AI (P = 0.035) but not to tumor size. Fas expression was significantly associated with high levels of AI (P = 0.014). In contrast, Bcl-2 expression was inversely associated with AI (P = 0.004). Expression of Bcl-2 and Fas did not show a statistically significant correlation with tumor grade, mitotic counts, or tumor size.


CONCLUSIONS
Apoptosis and Fas-ligand expression are statistically correlated to the histopathological grade of gastric smooth muscle tumors. This suggests that detection of apoptotic cells and Fas-ligand expression using the TUNEL assay or immunohistochemistry are useful for the evaluation of the malignant potential of gastric smooth muscle tumors.
Liu
Y
Y
Division of General Surgery, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan.
Chen
C
C
Chen
C
C
Hsieh
H
H
Chang
C
C
Shyu
J
J
Yen
C
C
Harn
H
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D053222:Fas Ligand Protein; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis*; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000473:pathology*; D009130:Muscle, Smooth; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D013274:Stomach Neoplasms / Q000473:pathology*; D019014:fas Receptor / Q000032:analysis
C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D019253:Proto-Oncogene Proteins c-bcl-2; D019014:fas Receptor