CD274 and neoplasm: Soluble PD-L1 in plasma is also considered as a potential diagnostic and predictive biomarker for tumor recurrence and prognosis (Chatterjee et al., 2017; Okuma et al., 2017; Zhou et al., 2017; Chang et al., 2019; Shigemori et al., 2019; Liu S. et al., 2020).