ERBB2 and cancer: We performed an exploratory analysis and compared collagen IV levels between HER2-positive (n=40) and HER-2 normal cancers (n=8) at baseline, there was no significant difference in the mean (166.3 vs 176 ng ml−1, P=0.61) or median (156.9 vs 169.2 ng ml−1, P=0.29) collagen IV levels between these 2 groups.