Type III interferons (IFN-III), including interferon lambda 1 (IFNL1or IL-29), have protein sequences and structures highly similar toIL-10.9 IFN-III are associated with immunomodulatoryeffects in various diseases, including autoimmune diseases, viralinfections, and cancer.10 For instance,IFN-III administration is reported to reduce the expression of Th2-associatedcytokines such as IL-13 in mouse models of autoimmune diseases. This evidence concerns the gene IFNL1 and cancer.