Figure 4.

Immunohistochemical staining of cancer stem cell markers revealed a significant difference between the primary lesion and metastatic subclavian lymph node. A and D. CD44 showed low expression in the primary lesion but high expression in the metastatic lesion, localized in both the membrane and cytoplasm of tumor cells (200×); B and E. CD24 showed high membranous expression in both the primary and metastatic lesions (200×); C and F. ALDH1 showed moderate expression in both nucleus and cytoplasm of tumor cells localized in the primary lesion; however, it showed high expression mainly localized to the cytoplasm of the metastatic lesion (200×). Abbreviations: ALDH1, aldehyde dehydrogenase; CD, cluster of differentiation.