XCR1 and medulloblastoma: Leucine-rich repeat containing G-protein-coupled receptor 5 (LGR5) is significantly over-expressed in the WNT subgroup of tumors (120-fold, p =0.01); additionally, our data suggest that it is mildly under-expressed in other groups of medulloblastoma, providing the benefit of being highly differentially expressed not only between WNT tumors and normal cerebella, but also between WNT tumors and other medulloblastoma groups (Additional file 3: Table S2; Figure 3).