IGFBP3 and breast cancer: All of the studies included [15, 16, 26–28] evaluated the serum concentrations of IGFBP-3 and demonstrated that exercise training significantly increased the serum levels of this biomarker in women with breast cancer (SMD = 0.54, 95 % CI 0.27 – 0.80; I2 = 84.2 %) (Fig. 5).