Comprehensive genomic and transcriptome analyses using next-generation sequencing(NGS)analysis has lead a discovery of a variety of novel driver gene mutations and new therapeutic targets for cancer patients, and has remarkably improved outcome of the patients through the development novel molecular targeting drugs. Even so, in so-called intractable or refractory cancers, those "druggable"alterations common to the diseases are rarely found due to the high diversity of the tumor. Furthermore, most of molecular target therapy is known to acquire the resistance to the drug by means of multiple factors such as up-regulation of the partially inhibited pathway, mutation of the target, activation of alternative pathways, histological translocation, and oncogene de-addiction. Understanding of intra-tumoral heterogeneity and tumor-stromal crosstalk in tumor microenvironment with consequence of biological network re-construction are also of key importance to overcome the resistance. These suggest the limitation of mono-layer OMIC approach focusing on genome and/or cancer cell alone to identify truly effective therapeutic target and biomarker. Under these circumstances,"Trans-OMICS" concept has emerged as a novel approach to clarify a global biochemical network across multiple omics layers(eg genome, transcriptome, proteome, and metabolome)directly correct with a variable phenotype by use of both multi-omic measurements and computational data integration. This approach has great potential for drug discovery and clinical implementation of omics-based cancer medicine. We introduce here the outline of technologies and analysis for Trans-OMICS approach, and review for the recent studies in oncology research with showing our recent attempt.