Since JAK activation promotes subsequent tyrosine phosphorylation of STAT proteins that form transcriptionally active STAT1 homodimers or STAT1/STAT2/IRF9 complexes20, the importance of protein ubiquitination in regulating cytokine signaling and IFN-mediated STAT signaling is underscored by the propensity of tumor cells and viruses to hijack this mode of regulation to evade IFN control and interfere with the ability of a host to suppress malignant growth and viral replication103,104. This evidence concerns the gene STAT1 and neoplasm.