LncRNA LINC00665 affected gastric cancer through Mir-9-5p according to CeRNA network analysis

Gastric cancer (GC) is one of the most common cancers in the world. Although the incidence and mortality rates of GC have declined globally in the past decades, its prognosis is still poor. Moreover, the exact mechanism of GC has not been thoroughly studied. This study aimed to identify central genes to improve the prognostic prediction of GC and construct a regulatory network of messenger RNA (mRNA), microRNA (miRNA), and long noncoding RNA (lncRNA). Six genes (COL10A1, CTHRC1, FAP, FNDC1, INHBA, and SULF1) were found using the information in the GEO database. The expression of these genes differs between patients with GC and nontumor groups, and such difference may affect the survival rate of patients with GC. A ceRNA network consisting of mRNA (CTHRC1, FNDC1, and INHBA), miRNA (mir-9-5p), and lncRNA (LINC00665) was constructed to reverse predict the target genes related to GC prognosis. According to the ceRNA theory, LINC00665 could bind with mir-9-5p in a competitive manner, increasing the transcription of CTHRC1, FNDC1, and INHBA regulated by mir-9-5p. However, this study has many limitations. First, age, sex, tumor stage, patient classification, and other factors were not considered when examining differentially expressed genes. Second, only FNDC1 expression in mRNA was shown.