Gastrointestinal tumors are high morbidity and mortality in the world. During carcinogenesis the activation of oncogenesandinactivation of tumor suppressor genes they are highly heterogeneous in molecular genetics and biological phenotype . It is the current aroused general interest research that discovery and identification of "driver genes" for gastrointestinal tumors as the biomarkers are applied to clinical application for early diagnosis, prognosis and treatment basis .
Pharmacogenomics and biomarkers testing are the cornerstones for implement “precise treatment”. Pharmacogenomics studies have shown that genotypes in individual is closely related to the efficacy of medicine andtoxic effects. Based on gene polymorphisms and mRNA expression we could implement“individualized chemotherapy”to improve over survival and reduce adverse effects.
Recent integrative genomic studies have revealed that 98% of the human genome transcripts are non-coding RNA (ncRNA) with limited or no protein coding capacity. Long nonoding RNAs (lncRNAs), with complex secondary and tertiary structure, greater than 200 nt are important new members of the ncRNA family. Researchers have demonstrated that the aberrant lncRNAs expression involve in diverse human diseasesin particular cancers. Mounting evidences showed that some lncRNAs epigenetically regulate gene expression by DNA methylation and histone modifications at various levelsincluding chromatin modification, transcription and posttranscriptional processing. LncRNAs are abnormally expressed in tumors and play an "oncogene" or "tumor suppressor gene" function to participate in proliferation, apoptosis , invasion and migration, immune escape and other pathological processes. Additional some LncRNAs expression levels are closely related to the prognosis of patients. It can be used as a molecular markers for diagnosis and prognosis. It is great significance to study the regulation mechanism of lncRNA to more recognize tumor development.
In 2015, Patrick Tan et al. published a study that epigenetic changes are one of the driving factors leading to the development of gastric cancer. As an important epiregulatory molecule, LncRNA is abnormally expressed in gastric cancer tissues, plasma and gastric juice. It plays an "oncogene" or "tumor suppressor gene" function to participate in progression of gastric cancer. Our datademonstrated that FEZF1-AS1 and HOTAIR could act as an “oncogene” for gastric cancer to promote proliferation and epithelial-mesenchymal transition.
These data provided new insights into the RNA regulation network, indicating that lncRNAs couldregulating gene expression.LncRNAs have been proposed as potential targets for prognosis and therapeutic intervention.