ANXA2 and cancer: ELISA analysis shows that exo-AnxA2 concentration was significantly elevated in serum samples of breast cancer patients (n = 169, 83.33 ± 2.040 ng/mL, P < 0.0001) in comparison to non-cancer (n = 68, 34.21 ± 2.238 ng/mL) females (Fig. 2a).