**3.16 Eukaryotic initiation factor 4E**

Available studies showed that any form of genetic variation should function at the protein level (Branhart&Simon, 2007). Therefore the relationship between eukaryotic cell (protein translation) initiation factor and tumors has aroused increasing attention, especially eukaryotic initiation factor 4E (eIF4E), which was believed to be more closely related to tumors (Sonenberg,2008). Data have shown that eIF4E can alter the amount of expression of some malignant tumor-related genes and is the determinant of malignant phenotype production. It promotes cells to surpass the limit of normal growth and undergo carcinogenesis through regulating the amount of translation of some specific malignancyrelated molecules (Culjkovic *et al,* 2006). Dong (Dong *et al,* 2009) used a vector carrying shRNA of survivin-targeted eIF4E to transfect human breast cancer cells, and found that not only the level of eIF4E mRNA and protein expression was decreased but tumor progressionrelated protein VEGF, FGF2 and CCND1 were also down-regulated markedly. The breast cancer tumor size of the intervention group using eIF4E-targeted shRNA was significantly smaller than that of the control group (233.5mm3 vs 397.7mm3, P<0.01). In addition, shRNA could also enhance the chemotherapy effect of cisplatin. The result showed that the tumor size of the cisplatin+shRNA plasmid combination group was significantly smaller than that of the plasmid control group (134.5mm3 vs 208.9mm3, P<0.01).
