Quantitative analysis of tyrosine hydroxylase mRNA for sensitive detection of neuroblastoma cells in blood and bone marrow.

BACKGROUND Sensitive monitoring of minimal residual disease may improve the treatment of neuroblastoma in children. To detect and monitor neuroblastoma cells in blood and bone marrow, we developed a quantitative method for the analysis of tyrosine hydroxylase mRNA. METHODS We used real-time reverse transcription-PCR. The calibrator was constructed from a segment of tyrosine hydroxylase mRNA that included the target. Blood and bone marrow samples from 24 children with neuroblastoma and 1 child with ganglioneuroma were analyzed. Controls were blood samples from the cords of 40 babies, from 58 children 6 months to 15 years of age, and from 34 healthy adults, as well as from 12 children with other diseases. RESULTS The detection limit was approximately 70 transcripts/mL. All 144 blood controls were below this limit. At diagnosis, blood tyrosine hydroxylase mRNA was higher in children with widespread disease (stage 4/4S; n = 6; range, 203-46,000 transcripts/mL) than in patients with localized disease (stages 1-3; n = 6; </=83 transcripts/mL; P = 0.002). Bone marrow from all five children with localized disease had concentrations <72 transcripts/mL, whereas five of six stage 4 patients had increased concentrations (6,000-8,000,000 transcripts/mL; P <0.05). In nine children in whom tyrosine hydroxylase mRNA was measured repeatedly, the results corresponded to the clinical course. CONCLUSION Quantitative analysis of tyrosine hydroxylase mRNA in blood and bone marrow is reliable and easy to perform and may be used for upfront staging, prognostic assessment, and treatment monitoring of neuroblastoma.