Several methods, such as assessing the expression of tumour cells, stromal cells, and both tumour and stromal cells or using different thresholds for positivity, have been tested in clinical trials.35–37 Second, we focused on the expression of PD-L1 as an inhibitory reaction of tumour cells to anti-tumour immune function and cytotoxic T cells, which attack tumour cells directly. The gene discussed is CD274; the disease is neoplasm.