New data sets are now available including RNA-Seq data from the TARGET acute myeloid leukemia project and single nuclei RNA-Seq data from the CPTAC program. These changes are summarized below:
In Data Release 34, the GDC released new data from the Beat AML and Clinical Proteomic Tumor Analysis Consortium (CPTAC) programs:
Any germline SNP calls are not available for exploration in the GDC Data Portal. Instead, alignments for germline data are available under controlled access. Users with appropriate access may use the alignments to generate germline variants.
Some somatic variants callers, such as MuTect2, also output somatic calls with some level of germline possibilities, such as those labelled as "germline_risk". Please note that these calls are, by no means, germline variants. They are somatic calls with boundary probability of germline risks.
For the reference genome, the GDC has been using an augmented version of GRCh38.p2 (with additional decoy sequences and virus sequences) since inception. The GDC does not use alternative contigs, and only derives high-level data from the major chromosomes, so the same reference genome is used for both gene model GENCODE v22 (from Data Release 1 to 31) and GENCODE v36 (from Data Release 32). As future versions of the reference genome are released, e.g., GRCh39, the GDC will evaluate the benefits of updating data to utilize the new version.
In GDC Data Dictionary Release 2.5.0, the GDC added support for:
In Data Release 33, the GDC released data from two new projects at the GDC:
Although GENCODE v22 data cannot be browsed in the GDC Data Portal, it can still be downloaded using the GDC Data Transfer Tool or API. You will need to either have a previous manifest or use known UUIDs to download v22 files.
The primary reasons for the fewer open-access mutations are from two strategies that improve quality: 1) TCGA is now using a 2-caller ensemble, instead of a single caller; 2) Removal of variants outside of the target capture region, instead of a combined “target capture + GAF exonic region”. Additionally, TCGA was the original project in which GDC open-access variants were produced and used variant rescue steps that only applied to TCGA. To keep the TCGA variant-calling pipeline consistent across projects, GDC is no longer rescuing MC3 and TCGA validation variants.
The gene model used as a reference across GDC has been updated from GENCODE 22 to GENCODE 36. GENCODE gene sets are continuously updated to improve the coverage and accuracy.
