IGF1 and breast cancer: Meanwhile, GSG2 knockdown inhibits the expression of anti-apoptotic proteins Bcl-2, Bcl-W, IGF-I, IGF-II, IGF-1SR, Livin, Survivin, STNF-R1 and TNF-β in BC cells (P < 0.05) (Additional file 1: Fig. S1B).