This downregulation was shown at both the protein level (ISGF3, MxA, MxB and MnSOD) as well as the mRNA level (seven constitutive and a further seven HRGβ1-dependent genes), and there was a strong inverse correlation between ErbB-2 expression and ISGF3G expression in the panel of breast tumour cell lines used. Here, MX1 is linked to breast neoplasm.