To support this evidence, different studies have shown that a high proportion of cancer and hepatitis C patients who receive cytokine including interferon-alpha (IFN-α) therapy develops symptoms of depression that are indistinguishable from those found in MDDs (Denicoff et al., 1987; Schäfer et al., 2007; Su et al., 2010; Udina et al., 2012; Valentine et al., 1998). This evidence concerns the gene IFNA17 and depressive symptom measurement.