AHR and neoplasm: To determine if our findings of a tumour-suppressive role for the AHR pathway may have direct clinical relevance, we examined the expression of AHR in a cohort of human medulloblastomas, profiled by the Clifford group, with the following subgroup distribution: WNT (n = 28), SHH (n = 58), Grp 3 (n = 59), Grp 4 (n = 95).