Although different factors, such as retinoic acid-inducible gene I (RIG-I) and Src homology 2 domain-containing protein tyrosine phosphatase-2 (SHP-2) are related to the induction of IFN expression, quercetin has been reported to enhance IFN-α expression and activate Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling in cancer cells. This evidence concerns the gene PTPN11 and cancer.