In the treatment of small cell lung cancer (SCLC), an aggressive neoplasm thought to be arising from lung neuroendocrine cells, several trial are ongoing to investigate PD-L1 and PD-1 expression patterns and the role of anti-tumour immunotherapy such as blockade of co-inhibitory immune pathways PD-1/PD-L1. This evidence concerns the gene CD274 and small cell lung carcinoma.