HIF1A and neoplasm: We also examined key PD‐L1 expression regulators intrinsic to the tumor cells that might be influenced by the drug [30], including soluble factors released by tumor cells such as EGF (epidermal growth factor) [31], cytokines like IFNβ (interferon‐β) [32] and IL‐6 (interleukin‐6) [33] and transcription factors like HIF‐1α (HIF1A) (hypoxia‐inducible factor 1‐α) [34, 35].