Summary: The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) projects produced large-scale RNA sequencing data, which provides an opportunity for performing integrated expression analysis for all genes across tens of thousands of tumor and normal tissue specimens. Rapid access to and easy visualization of such valuable data could facilitate research in a wide biological area. Here, we present the GE-mini APP for smart phones, a mobile visualization tool for integrated gene expression data based on both TCGA and GTEx. This gene-centric expression viewer provides a convenient method for displaying expression profiles of all available tumor and tissue types, while allowing drilling down to detailed views for specific tissue types. Availability and Implementation: Both the iOS and Android APPs are freely available to all non-commercial users in App Store and Google Play. The QR codes of App store and Google play are also provided for scanning and download. The GE-mini web server is also available at http://gemini.cancer-pku.cn/ . Contacts: [email protected] or [email protected]. Supplementary information: Supplementary data are available at Bioinformatics online.