Higher PD-L1 expression in only tumor cells was associated with larger tumor size (pooled RR: 1.89, 95% CI: 1.09–3.27; Fig. 3a), ER negativity (pooled RR: 0.26, 95% CI: 0.09–0.72; Fig. 3b), PR negativity (pooled RR: 0.27, 95% CI: 0.08–0.94; Fig. 3c), HER-2 positivity (pooled RR: 1.52, 95% CI: 1.06–2.18; Fig. 3d), and TNBC (pooled RR: 4.61, 95% CI: 1.08–19.63; Fig. 3e). Here, PGR is linked to neoplasm.