Loss of one copy of Dicer induced SHH medulloblastoma with a similar time of onset and penetrance in Dicerfloxed/+; Nestin-Cre+; Ptch1+/-; Cdkn2c+/- compared to Dicer+/+; Ptch1+/-; Cdkn2c+/- mice, 76.5% (39/51) versus 62% (31/50), respectively (Fig 6A). The gene discussed is PTCH1; the disease is medulloblastoma.