Chromosomal translocations involving the Mixed Lineage Leukemia (MLL) gene account for 80% of cases of acute lymphoblastic leukemia (ALL) in infants. Of the more than thirty ALL associated MLL translocation partners, approximately 50% exhibit a MLL-AF4 translocation, t(4;11)(q21;23). Another common MLL translocation partner is AF9, at t(9;11)(p22;q23). Significantly, an interaction between AF4 and AF9 proteins was identified and the interaction domains are included in the MLL-AF4 and MLL-AF9 translocations. A novel peptide inhibitor, PFWT, was designed from the minimum interaction domain of AF4 required for the formation of the AF4-AF9 complex. PFWT was shown to be effective at inhibiting the formation of the AF4-AF9 complex as well as inducing cell death in leukemia cell lines exhibiting t(4;11) chromosomal translocations. The mechanism of induced cytotoxicity by PFWT is unknown, but involves induction of necrotic cell death. Identification of a synergistic interaction of the peptide PFWT and inhibitors for which the mechanism of programmed cell death is known would be useful in elucidating the mechanism of PFWT stimulated cell death. Additionally, classification of the effects of PFWT on the cellular architecture would be beneficial for gaining an understanding of how PFWT is inducing necrotic cell death.