CD274 and neoplasm: The positive association between PD-L1 amplification and PD-L1 protein levels in tumor cells (median positive tumor cells 0% in the non-amplified group versus 15% in the PD-L1 amplification group, p < 0.001) (Supplementary Fig. 2C) as well as the correlation between the degree of PD-L1 amplification and protein level (r = 0.26, p < 0.001) (Supplementary Fig. 3) were confirmed in the Uppsala 95 cohort.