The effect of the single-chain alkylphospholipid perifosine was analyzed in p53(wild-type) (SKW6.4, OCI and MOLM), p53(mutated) (BJAB, MAVER) and p53(null) (HL-60) leukemic cell lines. Perifosine promoted cytotoxicity with a combination of apoptosis induction in all cell lines and cell cycle block at the G(2)M checkpoint, which was selectively observed in p53(mutated) BJAB and MAVER cell lines. At the molecular level, perifosine induced hypophosphorylation of retinoblastoma protein and the degradation of E2F1 protein in p53(mutated) but not in p53(wild-type) cells. These data indicate that perifosine potentially represents an innovative therapeutic approach for p53(mutated) hematological malignancies.