Where can I find mutation datasets for cancer?
As I'm sure you're aware, there is no complete centralised database for cancer gene mutations. The most comprehensive database is the TGCA as you've already mentioned. That doesn't mean that other data isn't out there.

A broad option that might fit your needs is to query OMIM hosted by NCBI. You can search "cancer" or something more specific and then select the dbSNP tab and it will return a list of gene locations of mutations that match the query.



For a more specific search, COSMIC hosted by SANGER allows downloads of the "cancer genes" in fasta format, and various other downloads with other information are available. It's manually curated which is always a bonus, however this does mean that it's limited to just a few genes. There is also BIC. This is specifically focussed on genes related to breast cancer and is hosted by NHGRI. Again, an account is required for the download and it is limited to genes affecting breast cancers.