〔Abstract〕 To investigate the expression of Ribosomal protein L26 ( RPL26) in gastric cancer cells (GC) and its effect on cell apoptosis and proliferation . Methods The expression of RPL26 in GES-1 and GC cell lines was detected by Western blot. GC cell line HGC-27 was used to construct RPL26 overexpression cell line , and GC cell lines HGC-27 and AGS cells were used to construct RPL26 knockdown cell line . The overexpression and knockdown efficiency of RPL26 were detected by Western blot. Cell counting kit-8 (CCK-8) , colony formation assay and Transwell assay were used to detect the effects of the overexpression and knockdown of RPL26 on the pro- liferation and migration of GC cells . Western blot was used to detect the expression of Phosphatidylinositol-3-kinase (PI3K) / protein kinase B (AKT) signaling pathway related factors PI3K , AKT , phosphorylated phosphatidylinosi- tol-3-kinase (p-PI3K) , phosphorylated protein kinase B ( p-AKT) and downstream factors B-Cell lymphoma-2 (Bcl-2) , Bcl-2 associated X protein (Bax) and Cyclin A , G1 /S-specific Cyclin D1(Cyclin D1) , Cyclin-depend- ent kinases (CDK)4 and CDK2 in overexpression and knockdown of RPL26 stably transfected cell lines . Results Compared with GES-1 , RPL26 was highly expressed in HGC-27 cells ( tHGC-27 = 4. 97 ; P < 0. 05) and elevated in AGS , but the difference was not statistically significant. In HGC-27 and AGS cells , CCK-8 and colony formation assays showed that the proliferation ability of cells decreased after the knockdown of RPL26. Transwell assay showed that the migration ability of cells decreased after the knockdown of RPL26. Western blot showed that Bcl-2 expression was decreased in HGC-27 , AGS cells after the knockdown of RPL26 ( tHGC-27 = 11 . 50 , tAGS = 4. 77 ; P < 0. 05) , and Bax expression increased ( tHGC-27 = 9. 63 , tAGS = 4. 05 ; P < 0. 05) . In HGC-27 cells , the ratios of p- PI3K/PI3K and p-AKT/AKT significantly decreased after the knockdown of RPL26 ( tp-PI3K/PI3K = 3 . 86 , tp-AKT/AKT = 8. 29 ; P < 0. 05) . Cyclin A , Cyclin D1 , CDK4 , CDK2 protein expressions decreased ( tCyclin A = 9. 61 , tCyclin D1 = 5 . 10 , tCDK4 = 11 . 64 , tCDK2 = 7 . 81 ; P < 0. 05) , while the overexpression of RPL26 in HGC-27 cells showed the op- posite trend . Conclusion The knockdown of RPL26 may arrest the cell cycle in G1 /S phase by inhibiting the PI3K/AKT signaling pathway , thereby inhibiting cell proliferation and promoting apoptosis .