PAPPA and breast cancer: The IGFBP-4/ IGF-I/PAPP-A axis along with follistatin-like (FSTL)-3 has been shown to be surrogate markers for BC in a study involving 100 females with benign tumors, 145 females with malignant tumors (including treatment naïve and chemotherapy treated) and 100 disease-free control individuals [97].