CD274 and neoplasm: Consistent with PD-L1 expression, we observed a more pronounced elevation of PKM2 mRNA and protein levels in PDAC cells after they were co-cultured with M2 macrophages (Figs. 3e, f and S3e).It has been reported that tumor cells favor PKM2 because it can switch between a highly active tetramer form and a less active dimer form.