CXCR4 and nasopharyngeal carcinoma: We observed different staining patterns of CXCR4 in NPC tumor cells: 135 showed nucleus staining, 18 nucleus and cytoplasm staining, 2 nucleus and cytoplasm and membrane staining, 14 cytoplasm staining, 22 cytoplasm and membrane staining, 2 membrane staining and one negative staining (Fig. 1, C, D and 1E).