Transition of the programmed death 1 pathway from the primary colorectal cancer to its corresponding pulmonary metastasis

Background and Objectives The inhibition of the programmed death 1 (PD‐1)/its ligand 1 (PD‐L1) pathway may be associated with clinical responses in colorectal cancer (CRC). We aimed to characterize the transition of PD‐1/PD‐L1 expression through pulmonary metastasis (PM) and its clinical relevance. Methods This study retrospectively reviewed 50 patients who had curative resection of primary CRC and its PM. We evaluated the presence of PD‐1+...