CD274 and breast cancer: As compared with noncancerous patients with low PD-L1 levels, BC cases with high PD-L1 levels showed low miR-145 and -335 levels, with Pearson correlation analyses revealing a clear inverse relation between miR-145 and -335 expression and PD-L1 mRNA level (r =  − 0.5431; P-value = 0.0013, r =  − 0.6207; P-value = 0.0002 respectively) (Fig. 3e).