POU5F1 and renal cell carcinoma: Therefore, we further investigated the mRNA and protein levels of OCT4 and ALDH1A1 in RCC cells co-cultured with NFs or CAFs, and found that RCC cells co-cultured with CAFs showed increased OCT4 and ALDH1A1 levels than cells co-cultured with NFs (Fig. 2F, G).