TYK2 and neoplasm: On the other hand, while TYK2 kinase activity is required for functional type I interferon responses in vivo [53], expression of the kinase-inactive mutant TYK2 K923E partially rescues NK cell-mediated anti-tumour response, thus supporting kinase-independent functions of TYK2 [54] that we cannot rule out for the variants analysed in the present study.