Growth curves of mammary tumors in vehicle- or PAX-treated Spp1+/- mice implanted with the indicated cells expressing control shRNA, and Spp1-/- mice implanted with the indicated cells expressing SPP1 shRNA. MDA231-LM2: control, PAX and SPP1 def. + PAX n = 16 tumors per group, SPP1 def. n = 14 tumors. SUM159-LM1: control, PAX and SPP1 def. + PAX n = 16 tumors per group, SPP1 def. n = 15 tumors. 