# TCGA open versus controlled data tiers

Source: https://onco.cc/terms/tcga-tiers/  
OnCo record `tcga-tiers` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

TCGA data comes in two tiers: open files (gene expression, somatic mutations, clinical tables, slide images) anyone can download, and controlled files (raw reads, germline variants) that need dbGaP approval.

## Summary

The GDC's access documentation divides its data into open access, which requires no authorisation and carries only a ban on attempting to re-identify participants, and controlled access, which requires an approved dbGaP application because the files could identify a person. Expression matrices, somatic MAFs, copy number segments, methylation betas, RPPA and diagnostic slides are open; BAM files and germline calls are controlled. Most public cancer models are trained entirely on the open tier.

## Fields

- Kind: Term
- Last checked: 2026-09-24
- Also known as: TCGA open tier; TCGA controlled tier; open-access tier; open access data tier; controlled tier; GDC open data; GDC controlled data
- Tags: cansim-terms

## Notes

- Listed in the CanSim terms map 1.0.0 (docs/onco/terms.json, generated 2026-09-24), CC BY 4.0, attribution: CanSim project, an open, public-data-first cancer foundation-model programme; CanSim page path /terms/tcga-open-vs-controlled-tiers.

## Sources

- GDC: obtaining access to controlled data: https://gdc.cancer.gov/access-data/obtaining-access-controlled-data
- NCI Genomic Data Commons API (data-sources): https://gdc.cancer.gov/developers/gdc-application-programming-interface-api

## Connected records

- collections: [TCGA / NCI Genomic Data Commons](https://onco.cc/collections/tcga-gdc/)
- terms: [Cancer AI vocabulary (CanSim terms map)](https://onco.cc/terms/cancer-ai-vocabulary/), [Controlled-access genomic data (dbGaP, EGA)](https://onco.cc/terms/controlled-access-data/), [Data use agreements and consent for research use](https://onco.cc/terms/data-use-agreements/), [TCGA barcode](https://onco.cc/terms/tcga-barcode/)

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JSON: https://onco.cc/api/v1/entities/tcga-tiers.json