PDCD1 and colon carcinoma: Additionally, as reported by Rosenbaum et al, colon carcinomas harboring BRAFV600E mutation are also characterized by the expression of programmed cell death 1(PD-1) and its ligand (PD-L1), microsatellite instability and a peculiar medullary morphology with frequent CD-8 positive tumor-infiltrating lymphocytes.