Across TCGA pan-cancer cohorts, IL9 RNA differs between tumor and matched normal tissue in 4 of 18 cancer types tested, making tumor–normal expression one of IL9’s most consistent transcriptional readouts.
The strongest signal is observed in kidney chromophobe (KICH), where IL9 RNA is repressed in tumor relative to normal tissue. In most cancer types IL9 is over-expressed in tumor, although a few such as KICH and KIRP show the opposite, repressed pattern.
KICH, KIRP, and LUSC are the cancer types where IL9 tumor–normal differential expression is most reproducible.