title: Competitive reverse transcription-polymerase chain reaction assay for quantification of human multidrug resistance 1 (MDR1) gene expression in fresh leukemic cells.
abstract: We have analyzed MDR1 gene expression in 69 clinical samples obtained from 64 patients with leukemic hematologic malignancies by using a competitive reverse transcription-polymerase chain reaction assay with a heterologous competitor RNA. To exclude a false-positive result caused by concomitant normal lymphocytes that physiologically express MDR1, in samples we determined a cut-off value of 8 amol MDR1 transcript per microgram of RNA by simultaneous measurement of rhodamine 123 dye efflux either in lymphocyte or gated leukemic cell populations. Consequently, 23 of 69 samples were concluded to be MDR1-positive in leukemic cells per se. The MDR1 expression rate was significantly correlated with factors such as a history of preceding chemotherapy, elder age of the patient, and certain disease types (eg, leukemia progressed from myelodysplastic syndrome). Moreover, the complete response rate after chemotherapy was significantly higher in MDR1-negative patients than in MDR1-positive patients (52% vs 17%, respectively; P = .01). The assay established will enable the quantification of MDR1 gene expression in blood samples from patients with leukemic hematologic malignancies and will be applicable to clinical laboratories as a routine test.
authors.affiliation: Department of Laboratory Medicine, National Defense Medical College, Saitama, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Takemura
authors.forename: Y
authors.initials: Y
authors.lastname: Kawai
authors.forename: H
authors.initials: H
authors.lastname: Miyachi
authors.forename: M
authors.initials: M
authors.lastname: Kawabata
authors.forename: T
authors.initials: T
authors.lastname: Matsumura
authors.forename: T
authors.initials: T
authors.lastname: Yamashita
authors.forename: S
authors.initials: S
authors.lastname: Mori
authors.forename: K
authors.initials: K
authors.lastname: Furihata
authors.forename: S
authors.initials: S
authors.lastname: Shimodaira
authors.forename: K
authors.initials: K
authors.lastname: Motoyoshi
authors.forename: T
authors.initials: T
authors.lastname: Hotta
authors.forename: S
authors.initials: S
authors.lastname: Sekiguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Ando
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000097:blood; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002648:Child; D002869:Chromosome Aberrations; D019450:Genes, MDR; D006801:Humans; D007938:Leukemia / Q000097:blood* / Q000188:drug therapy / Q000235:genetics*; D008214:Lymphocytes / Q000097:blood; D008875:Middle Aged; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D000970:Antineoplastic Agents