(a) Negative CD133 in clear cell RCC
(b) +CD133 in CCP-RCC
(c) + CD133 and OCT3/4 in CCP-RCC
(d) CD133 in peritumoral tubules (arrows)
Figure 5: CD133 expression in clear cell papillary renal cell carcinoma (RCC). CD133 stained negatively in a clear cell RCC (a) but showed diffuse cellular membrane expression of CD133 (monoclonal) in clear cell papillary RCC (b). The clear cell papillary RCC cells also demonstrated coexpression of CD133 (polyclonal) and OCT3/4 (monoclonal), another stem cell marker in the same tumor cells (c). CD133 was expressed in clear cell papillary RCC and regenerative tubules at the peritumoral area (d) (magnification ×400, (a)–(c); ×200, (d)).