FTO and breast cancer: For early-stage BC patients (Stage I + II, n = 79), we assessed the diagnostic value of FTO, PIK3CB, CEA and CA15-3 (AUCFTO = 0.646 [0.556–0.737], AUCPIK3CB = 0.751 [0.670–0.831], AUCCEA = 0.792 [0.716–0.868], AUCCA15-3 = 0.772 [0.696, 0.848], Table 5 and Fig. 3D).