We extracted total RNA from clinical samples of 42 normal gastric epithelial tissues and 60 gastric cancer tissues. The results of quantitative reverse transcriptase- polymerase chain reaction (qRT-PCR) were consistent with those of TCGA analysis. Clinical data analysis showed that the expression of LncRNA CASC15 was correlated with the total survival, tumor size and TMN staging in clinical patients. Clinical data analysis showed that the expression level of CASC15 was correlated with tumor size and TNM stage in clinical patients. Compared with the negative control group, the proliferation and cell cloning ability of MKN28 cells overexpressing LncRNA CASC15 significantly increased,indicating that overexpression of LncRNA CASC15 promoted the proliferation of MKN28 cells.