Tumor grading and expression of CD44 and CD24 in selected tongue tissues. Top panel (a-c): H&E staining for diagnosis and grading of tongue lesion or tumors. Middle panel (d-f): CD44 staining. Lower panel (g-i): CD24 staining. The cells in the basal layer expressing CD44 (black arrows) are negative for CD24 (black arrows). Magnification 40x.