ABCB6 and glioma: Moreover, we found a significant decrease of ALAD (10.33 ± 0.49 vs. 10.92 ± 0.56; p < 0.0005), UROS (9.08 ± 0.59 vs. 9.60 ± 0.51; p < 0.005) and ABCB6 (9.61 ± 0.45 vs. 9.82 ± 0.43; p = 0.019) in WHO grade IV gliomas.