| Abstract: |
Epipodophyliotoxins are associated with leukemias characterized by translocations of the MLL gene at chromosome band 11q23 and other translocations. Cytochrome P450 (CYP) 3A metabolizes epipodopbyllotoxins and other chemotherapeutic agents. CYP3A metabolism generates epipodophyllotoxin catechol and quinone metabolites, which could damage DNA. There is a polymorphism in the 5' promoter region of the CYP3A4 gene (CYP3A4-V) that might alter the metabolism of anticancer drugs. We examined 99 de novo and 30 treatment-related leukemias with a conformation-sensitive gel electrophoresis assay for the presence of the CYP3A4-V. In all treatment-related cases, there was prior exposure to one or more anticancer drugs metabolized by CYP3A. Nineteen of 99 de novo (19%) and 1 of 30 treatment-related (3%) leukemias carried the CYP3A4-V (P = 0.026; Fisher's Exact Test, FET). Nine of 42 de novo leukemias with MLL gene translocations (21%), and 0 of 22 treatment- related leukemias with MLL gene translocations carried the CYP3A4-V (P = 0.016, FET). This relationship remained significant when 19 treatment- related leukemias with MLL gene translocations that followed epipodophyllotoxin exposure were compared with the same 42 de novo cases (P = 0.026, FET). These data suggest that individuals with CYP3A4-W genotype may be at increased risk for treatment-related leukemia and that epipodophyllotoxin metabolism by CYP3A4 may contribute to the secondary cancer risk. The CYP3A4. W genotype may increase production of potentially DNA-damaging reactive intermediates. The variant may decrease production of the epipodophyllotoxin catechol metabolite, which is the precursor of the potentially DNA-damaging quinone. |
| Keywords: |
adolescent; adult; child; child, preschool; leukemia; gene translocation; human cell; major clinical study; dna-binding proteins; cancer risk; united states; antineoplastic agent; polymerase chain reaction; neoplasms; phenotype; dna damage; etoposide; antineoplastic agents, phytogenic; genotype; cyclophosphamide; ifosfamide; vinblastine; transcription factors; leukemogenesis; vindesine; drug metabolism; neoplasms, second primary; karyotyping; chromosomes, human, pair 11; chromosome 11q; teniposide; chromosome mapping; dna polymorphism; continental population groups; mixed function oxygenases; ethnic groups; proto-oncogenes; myeloid-lymphoid leukemia protein; cytochrome p450 isoenzyme; podophyllotoxin; epipodophyllotoxin; cytochrome p-450 enzyme system; quinine; humans; human; male; female; priority journal; article; staphylococcus phage 3a; martes pennanti; cinchona pubescens
|
