RNA seq TCGA

[manasarai2009]

Hi

I have downloaded the RNA seq data RPKM values from TCGA. For each gene
RAW COUNTS, MEDIAN LENGTH NORMALIZED, RPKM VALUES were given. I understood the raw counts and rpkm values, but i do not clearly understand what are these median length normalized values. could anyone please let me know....

Example:

GENE raw_counts median_length_normalized RPKM
ACOT7|11332_calculated 1835 55.9325 7.4205
ADAR|103_calculated 29550 328.378 43.5654

[Richard Finney]

https://tcga-data.nci.nih.gov/tcgafiles/ftp_auth/distro_ftpusers/anonymous/tumor/brca/cgcc/unc.edu/illuminahiseq_rnaseqv2/rnaseqv2/unc.edu_BRCA.IlluminaHiSeq_RNASeqV2.mage-tab.1.6.0/DESCRIPTION.txt

Step 5: Calculate quantification at the gene level.

Quantification at the gene level is determined by collapsing the transcript
level quantifications onto their associated gene loci. Raw read counts,
coverage, and RPKM are reported for each gene. Raw read counts for a given
GeneX is the sum of reads aligned to all transcripts associated with that
gene. Coverage for a given GeneX is determined by: sum of bases aligned to
all transcripts associated with GeneX / length of GeneX. RPKM for a given
GeneX is calculated by: (raw read counts × 10^9) / (total reads × length of
GeneX). “Total reads” is the lane yield after removing poor quality reads.
In both the coverage and RPKM calculations, the length of GeneX is defined as
the median length of all transcripts associated with GeneX.