High level OPN-c appeared to be more significantly associated with poor survival (HR = 2.14, 95% CI: 1.51–3.04, and P < 0.0001; fixed-effects model) with undetected heterogeneity (I2 = 0%). Conclusions. Our analyses indicated that both OPN and OPN-c could be considered as prognostic markers for breast cancers. Here, SPP1 is linked to breast cancer.