Expression of CD44 in cancer cells. The tissue sections of 4 human clear cell renal cell carcinomas were routinely stained with hematoxylin and eosin or immunofluorecently stained with antibody against CD44 (green color). DAPI (4′,6-diamidino-2-phenylindole) stained the nucleus (blue color). Confocal imaging analysis reveals the morphology of cancer cells. Notably, CD44 was commonly observed in the invasive margin of cancer nests. The scale bar represents 100 μm.