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Understanding Data Access
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* **Public Data**  Sometimes the word "public" is misinterpreted as meaning "open".  All of the TCGA data is *public* data, and much of it is *open*, meaning that it is accessible and available to *all* users; while some low-level TCGA data is *controlled* and restricted to authorized users.
* **Open-Access Data**  Depending on how you categorize the data, *most* of the TCGA data is open-access data.  This includes all de-identified clinical and biospecimen data, as well as all Level-3 molecular data including gene expression data, DNA methylation data, DNA copy-number data, protein expression data, somatic mutation calls, etc. 
* **Controlled-Access Data**  All low-level sequence data (both DNA-seq and RNA-seq), the raw SNP array data (CEL files), germline mutation calls, and a small amount of other data are treated as *controlled* data and require that a user be properly authenticated and have dbGaP-authorization prior to accessing these data.