What is the ICGC normalized_read_count?
By reading this thread on seqanswers and by comparing the data to TCGA, I figured out


raw_read_count is the read count which you use as input for e.g. DESeq2. It has been estimated using RSEM
normalized_read_count is equivalent to the scaled_estimate from TCGA. This is the estimated fraction of transcripts made up by a given gene, as estimated by RSEM. Multiplying this value with 1e6 yields the TPM.