PHF6 encodes a member of the plant homeodomain (PHD)-like finger (PHF) family with two PHD-type zinc finger domains, indicating a potential role in transcriptional regulation. It is localized to the nucleolus and may play a role in recognizing methylation status of histone lysines. Somatic, nonsense, frameshift and occasional missense mutations throughout PHF6 have been reported in up to 38% of cases of T cell acute lymphoblastic leukemia. In T-ALL, PHF6 mutations often co-exist with NOTCH1 mutations. PHF6 mutations have also been reported in approximately 3% of cases of acute myeloid leukemia, less than 5% of chronic myeloid leukemia in blast phase, and 3% of myelodysplastic syndrome. In acute myeloid leukemia, PHF6 mutations have been associated with male preponderance and reduced overall survival in patients with normal karyotype or intermediate-rish cytogenteics abnormalities. Mutated PHF6 is more frequent in MDS cases with excess blasts, but there appears to be no association with survival (NCCN Guidelines for Myelodysplastic Syndromes). PHF6 mutation status does not appear to affect outcome in T-ALL according to some studies.