IFNA2 and fibrosarcoma: The function of the five missense alleles was then analyzed in cell lines: a TYK2-deficient HEK293T cell line for the IFN-α and IL-10 signaling pathways and a TYK2-deficient fibrosarcoma cell line stably expressing the IL-12R heterodimer (IL-12Rβ1 and IL-12Rβ2) or IL-23R (IL-12Rβ1 and IL-23R) for IL-12 and IL-23 signaling, respectively.