FBXL21P and medulloblastoma: However, using the Megasample application of the R2 Genomics program, we were able to compare the expression of FBXL21 in medulloblastoma (Pfister and Gilbertson datasets) to normal brain (Berchtold) and normal cerebellum (Roth dataset) using the same gene chip (Affytmetrix u133p2) and the same reporter (1555412_at).