POU5F1 and neoplasm: The explanations were: PD-1 inhibitor alone repressed tumor growth generally regardless of the OCT4 and SOX2 expressions on tumor cells, therefore it less affected the OCT4 and SOX2 expressions; while OCT4&SOX2 CTLs alone or in combination with PD-1 inhibitor could selectively repress OCT4/SOX2 expressed tumor cells, therefore, their expressions were lower.