[Expression and clinical significance of apoptosis associated genes Livin and Smac/DIABLO in human gastric carcinomas].

BACKGROUND AND OBJECTIVE

The proapoptotic gene Smac/DIABLO interacts with inhibitor of apoptosis protein Livin, which may contribute to regulating the impetus and progression of canceration. This study was to investigate the expression of Livin and Smac/DIABLO, and their correlations to the clinicopathological features in gastric adenocarcinomas.

METHODS

The expression levels of Livin and Smac/DIABLO mRNA in 75 gastric carcinoma specimens, 20 normal gastric tissues and 20 para-cancerous tissues were detected using the SYBR green real-time fluorescent quantitative reverse transcriptase PCR. The protein expression and location of Livin and Smac/DIABLO were measured by western blot and immunohistochemistry (SP method).

RESULTS

The expression of Livin mRNA was significantly up-regulated in gastric carcinomas (6.374+/-4.759) compared with the control. The expression of Livin was higher in poorly differentiated gastric carcinomas and carcinomas with lymph node metastases than in highly differentiated gastric carcinomas and carcinomas without lymph node metastases. (Chi2=9.60, P<0.01; Chi2=5.51, P<0.05). The expression of Livin mRNA had no correlation to tumor site, and the invasion depth and TNM stage (P >0.05). In contrast, no expression of Livin was detected in normal and para-cancerous gastric tissues. The protein expression of Livin was consistent with that of its mRNA expression. The expression level of Smac/DIABLO mRNA was lower in gastric carcinomas (0.731+/-0.420) than in normal gastric tissues (1.104+/-0.276) and para-cancerous tissues (1.061+/-0.737), but there was no significant difference (P>0.05). The expression of Smac/DIABLO mRNA was not correlated to clinicopathological characters of gastric adenocarcinoma. The protein expression of Smac/DIABLO was not completely consistent with that of its mRNA expression. The expression of Smac/DIABLO was different between intestinal type gastric carcinoma (84.38%) and diffuse type gastric carcinoma (60.65%) (P<0.05).

CONCLUSION

The expression and correlation of Livin and Smac/DIABLO vary in different stages and pathological types of gastric carcinoma. Overexpression of Livin is closely related to differentiation and metastases of gastric carcinoma.