Regulation of PD-L1(CD274) expression

The PD-L1(CD274)/PD1 pathways play a pivotal role in the regulation of normal T cell function as well in diseases like Cancer. It is a major co-inhibitory checkpoint signalling that regulates T cell activities and maintains immune homeostasis thus preventing autoimmunity in normal physiology and this same machinery is hijacked in disease like cancer to evade T-cells immunity against cancer cells. Under normal physiological conditions, PDL-1 (CD274) binds with its receptor PD1 and inhibits TCR and costimulatory signalling, thus inhibiting T cell activation (Arasanz et al. 2017, Riley et al.,2009, Sharpe et al., 2018). This regulation helps in the maintenance of immune tolerance. PDL1 (CD274) is normally expressed by antigen presenting cells APCs but it's also found to be expressed by non-immune cells like cancer cells (Cha et al., 2019, Chen et al., 2016. Expression of PDL1 is highly up regulated in cancers to evade the immune response by T cells thus making it a critical target for cancer treatment which leads to rapid FDA approval of drugs targeting PDL1/PD1 pathway (Ju et al., 2020, Yamaguchi et al. 2023, Wu et al.,2021). Expression of PDL1 is tightly controlled at epigenetics, transcriptional, translational and post translational level in normal condition but cancer cells utilise this regulation to induce PDL1 expression on its surface..

Summary from Reactome (R-HSA-9909648), read 2026-09-23.