SIX1 and neoplasm: Sufficient DNA was available on 16/19 MLLT1-mutant tumours to perform mutation analysis for WT1, CTNNB1, WTX, DROSHA, DGCR8, and SIX1/2 and this revealed five CTNNB1 mutations, one WTX mutation, and no WT1 DROSHA, DGCR8, or SIX1/2 mutations.