I do not see the app available from the Cy3 Apps Store; so looks you are to build it from sources.
Normally, one would not have to build the cbioportal-client though (if it's probably available in a public Maven repository).
If not, build it first (see below; but in my case, mvn install fails due to a junit test fails).
(you need a Mercurial client installed or e.g., SourceTree application. You also need Maven 3.0.x installed and JDK6) but downloading the sources archive might work as well.
Switch to the directory where the sources were placed, and execute:
cd cbioportal-client
mvn clean install
Then, switch to the mondrian-cy3-app in the directory where the sources are and execute:
cd ../mondrian-cy3-app
mvn clean install
- if it not failed (it fails for me...), the apps's JARs will be created in the mondrian-cy3-app/target/ and cbioportal-client/target/ sub-directories (e.g. cbioportal-client-0.0.1-SNAPSHOT.jar).
Now, start Cstoscape 3.0.2 (or 3.1 snapshot build), bring the Apps Manager UI (using Apps menu), and install the app(s) from JAR(s).
Hope it helps (otherwise wait for the authors to reply here or contact them directly;
I suspect the app, as it is now, won't start in Cy3 due to possible dependencies issues...)
Igor R.