Discovery of Population-Specific Translational Biomarkers among Korean Gastric Cancer Patients

Abstract

Gastric cancer is one of the most commonly occurring cancers in the world, with an increased incidence and mortality, especially according to modern people's diet and busy lifestyle. In particular, the Koreans targeted in this study, gastric cancer occupies the leading cause of death in the entire cancer group and showing the record (2018. Statistics of causes of death). It is necessary to discover specific gastric cancer biomarkers for Koreans to predict the diagnosis of gastric cancer through the results of a study by the American Cancer Control Association (ACSI, 2009), in which the incidence and cause of different types of cancer differ to the biomarkers by comparing the difference in gene expression between the normal RNA group and the gastric cancer group. NGS-based RNA-seq analysis was used as a method to see the difference in gene expression from RNA. Regarding RNA expression, analysis is performed using RNA expression data of TCGA database and Korean FASTQ data of NCBI SRA database to discover Korean gastric cancer biomarkers. In the TCGA, data on gastric cancer was analyzed as RNA-seq expression data for 3 races (Asia, Caucasian, and Black). We were proceeding with the analysis of normal samples and type-specific gastric cancer samples, extracted differentially expressed genes in Asia. For SRA, FASTQ data from the Korean Gastric Cancer Project (Accession: PRJNA435914) were used and RNA-seq analysis wes performed. The RNA-seq pipeline wes being analyzed in the same method as the TCGA RNA-seq pipeline, and normal samples and gastric cancer samples are analyzed in groups. Genetic biomarkers for Korean-specific gastric cancer based on TCGA gastric cancer data by substituting it into the list of Korean differentially expressed genes to which a random forest model was applied for the Asian-differentiated expression genes selected by the AUC filter. Genes showing the statistically most significant value were confirmed in the three genes CIP2A, LDHD, and KIFC1. In addition, we were searching for g; profiler Annotation and GeneMANIA network for excavated genes, and derived the function of the pathway containing the Korean-specific genes. Three TCGA-based Korean-specific genes extracted through this study (CIP2A, LDHD, KIFC1) and three g;profiler results (KEGG: 00260, GO: 0061846, GO: 0061845) and two GeneMANIA Network while hoping that the results will be utilized as a biomarker for the prediction of gastric cancer diagnosis in Koreans in the future. Through the study of these RNA-seq, it was possible to recognize the difference between races in gastric cancer patients, in particular, gastric cancer appears to be more common in Asians than in whites and blacks. We expectd more and more safe and accurate biomarkers are researched for Asian and Korean.