Concordance of Pharmacogenetic Polymorphisms in Tumor and Germ Line DNA in Adult Patients with Acute Myeloid Leukemia

Abstract

Archived tumor tissue is a useful resource for retrospective studies addressing relationships between genetic polymorphisms and treatment outcomes. However, genotypes determined in tumor and somatic tissues may differ due to cytogenetic and molecular changes associated with malignant transformation and progression. Discordance between germ line and tumor genotypes may be particularly relevant in leukemia because cytogenetic abnormalities are frequent. We compared genotypes determined in DNA extracted from paired pretreatment bone marrow and buccal samples from 80 adult patients with acute myeloid leukemia (AML). Paired AML and buccal DNA samples were genotyped for polymorphisms (21 single nucleotide polymorphisms and 2 gene deletions) on genes encoding proteins involved in drug metabolism (CYP3A4, CYP2C8, CDA, and GSTP1), oxidative stress mechanisms (CAT, MnSOD, GSTT1, GSTM1, GSTA1, and GPX1), drug transport (MDR1, MRP1, and BCRP), and DNA repair (MGMT, XPD, and XRCC1). Genotypes were determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, except GSTM1 and GSTT1, for which deletion genotypes were determined using multiplex PCR. Concordance of genotypes was tested by kappa statistics. kappa statistics for paired AML and buccal DNA samples ranged between 0.94 and 1.00, indicating excellent agreement. The GSTT1 and GSTM1 genotypes were in perfect concordance for the paired samples. Agreement was also excellent for genes at AML chromosome deletion and translocation breakpoints, including MDR1 at 7q21.1 and MRP1 at 16p13.1. Based on these data, genotypes derived from archived AML bone marrow samples were not likely to differ from those from genomic DNA, and archived bone marrow samples may be useful for the conduct of retrospective pharmacogenetic studies.