EGFR and neoplasm: Reconstitution of the gut microbiome of germ-free mice by transfer of fecal material from patients responding to therapy led to improved tumor control, augmented T-cell responses, and increased efficacy of anti-PD-1 therapy.83 However, some bacteria can activate the expression of the epidermal growth factor receptor (EGFR) by increasing the release of heparin-bound epidermal growth factor (HB-EGF).84 Activation of the EGFR/RAS pathway promotes PD-L1 transcription and expression in tumor cells,85 which undoubtedly decreases the efficacy of anti-PD-L1 therapy.