KRAS and lung carcinoma: Mutations in KRAS repress IRF2, facilitating the appearance of resistance mechanisms to anti-PD-1 immunotherapy.226 Additionally, in KRAS mutant lung cancer, oncogenic KRAS enhances programmed-death ligand 1 (PD-L1) expression via sustained p-ERK activation248–250 and by stabilizing its mRNA through the negative regulation of AU-rich element-binding protein tristetrapolin (TTP).