Across TCGA pan-cancer cohorts, IL21 mass-spec protein differs between tumor and matched normal tissue in 1 of 18 cancer types tested, making tumor–normal expression one of IL21’s most consistent transcriptional readouts.
The strongest signal is observed in lung squamous cell carcinoma (LSCC), where IL21 mass-spec protein is more highly expressed in tumor relative to normal tissue. In most cancer types IL21 is over-expressed in tumor.
LSCC are the cancer types where IL21 tumor–normal differential expression is most reproducible.