FN1 and breast cancer: FN levels in plasma were significantly higher in patients with BC in the test set than in all controls (absorbance at 450 nm (A450) median 0.84, interquartile range (IQR) 0·75–1·57; mean 1.1, standard deviation (SD) 0·33; p <0·0001; Figure 3A) including healthy control (A450 median 0.45, IQR 0·42–0.62; mean 0.53, SD 0·22; p <0·0001; Figure 3A); values differ significantly between the disease control groups (benign breast tumors n=20, and non-cancerous diseases n=30) and health control (Figure 3A and 3B, (healthy controls n=30,).