Across TCGA pan-cancer cohorts, SPDL1 mass-spec protein differs between tumor and matched normal tissue in 3 of 18 cancer types tested, making tumor–normal expression one of SPDL1’s most consistent transcriptional readouts.
The strongest signal is observed in head and neck squamous cell carcinoma (HNSC), where SPDL1 mass-spec protein is more highly expressed in tumor relative to normal tissue. In most cancer types SPDL1 is over-expressed in tumor, although a few such as LUAD show the opposite, repressed pattern.
HNSC, LSCC, and LUAD are the cancer types where SPDL1 tumor–normal differential expression is most reproducible.