Somatic mutations in plant homeodomain finger protein 6 (PHF6) gene have recently been reported in T-cell acute lymphoblastic leukemia (T-ALL), strongly suggesting its role in the pathogenesis of human cancers.To see whether the PHF6 mutation occurs in other malignancies, we analyzed entire coding sequences of PHF6 in 231 hematologic malignancies [105 acute myelogenous leukemias (AML), 66 pre-B-ALL, 23 T-ALL, one undifferentiated acute leukemia and 36 multiple myelomas] by single-strand conformation polymorphism assay. Also, we analyzed the mutation in 236 solid cancers, including 41 lung, 39 hepatocellular (HCC), 36 breast, 40 colorectal, 40 gastric and 40 prostate carcinomas.In the hematologic malignancies, there were 11 PHF6 mutations that were detected not only in T-ALL (34.7%) (five adult and three childhood T-ALL), but also in two AML (1.9%) (one acute monocytic leukemia and one AML minimally differentiated). In addition, there was a PHF6 mutation in the HCC (2.6%). The PHF6 mutations were detected in both male and female patients, and consisted of six frameshift, three nonsense and two intron mutations.Our data suggest that PHF6 mutation might play a role in tumorigenesis not only of T-ALL, but also of AML and HCC.