Therefore, candidate defects include variation in expression/function of the Type I receptor, IFNAR1, which is known to vary in breast cancer and this variation correlates with prognosis,43 or aberrant expression of interferon regulatory factors (IRFs), which act to modulate the range and extent of IFN-target gene activation, and are also known to be deregulated in breast cancer.44 The gene discussed is IFNA1; the disease is breast cancer.