After testing the system in 22Rv1, LAPC4, DU-145 (PCa), CAMA-1 (breast cancer) and SW780 (bladder cancer) cell lines, we observed that orientation A provided the highest reporter gene signal while also being specific to PCa cells due to PCA3-driven Cre expression (Figure 3B). This evidence concerns the gene PCA3 and urinary bladder cancer.