FNDC5 and cancer: In the pooled group analysis comparing cancer-free participants to patients with either recently identified or known breast malignancy under treatment, the only independent predictors were age (odds ratio (OR) = 1.05, 95% confidence interval (95% CI) = (1.02, 1.08), p < 0.01) and irisin levels (OR = 5.30, 95% CI = (1.24, 22.38), p=0.03) (Table 3).