Quantification of Wilms’ tumor 1 mRNA by digital polymerase chain reaction

Wilms’ tumor 1 (WT1) is overexpressed in various hematopoietic tumors and widely used as a marker of minimal residual disease. WT1 mRNA has been analyzed using quantitative real-time polymerase chain reaction (real-time PCR). In the present study, we analyzed 40 peripheral blood and bone marrow samples obtained from cases of acute myeloid leukemia, acute lymphoblastic leukemia, and myelodysplastic syndrome at Sapporo Medical University Hospital from April 2012 to January 2015. We performed quantification of WT1 was performed using QuantStudio 3D Digital PCR System (Thermo Fisher Scientific‎) and compared the results between digital PCR and real-time PCR technology. The correlation between digital PCR and real-time PCR was very strong (R = 0.99), and the detection limits of the two methods were equivalent. Digital PCR was able to accurately detect lower WT levels compared with real-time PCR. Digital PCR technology can thus be utilized to predict WT1/ABL1 expression level accurately and should thus be useful for diagnosis or the evaluation of drug efficiency in patients with leukemia.