For the HER2+ group, none of the three candidate biomarkers were associated with relapsed breast cancer in a univariate logistic regression of log transformed serum concentrations of CRP (OR 1.10, 95% CI 0.69–1.77, p = 0.683), SAA (OR 0.85, 95% CI 0.43–1.70, p = 0.655), or IL-6 (OR 1.99, 95% CI 0.69–5.73, p = 0.201). Here, IL6 is linked to breast cancer.