ABCB1 and central nervous system cancer: de Faria and coworkers44 showed that ABCC1 and ABCB1 were differently expressed in low-grade versus high-grade gliomas, ABCB1 expression levels were higher in glioma grade I and II, while ABCC1 expression was comparatively lower; and the reverse was true in higher grades, grade III but even more so in glioma grade IV (glioblastoma), which had the highest expression of ABCC142.