Fig. 1

workflow of the CASTIN algorithm. Total RNA extracted from cancer xenograft mouse model, which contains both human and mouse RNA, is sequenced using next generation sequencing. a Human (cancer) cell- and mouse (stromal) cell-derived transcripts are differentially assigned. b Accurate gene expression level is estimated using GC contents, distance from poly-A tails and originally defined mappable regions among annotated transcripts. c gene expression levels are integrated with an in-house ligand-receptor interaction database. d three indices (signal strength, ligand dependency, and receptor dependency) for quantitative evaluation of the interaction are calculated for the two directions of signal transduction and plot for visualization