Application of allele-specific quantitative PCR using genomic DNA to monitor minimal residual disease based on mutant gene levels following allogeneic hematopoietic stem cell transplantation in patients with hematological malignancies: comparison of mutant levels with autologous DNA percentage by short tandem repeat-PCR.

BACKGROUND

Quantitative evaluation of minimal residual disease (MRD) following hematopoietic stem cell transplantation (HSCT) is indispensable for patients with hematological malignancies. In addition to established MRD markers such as immunoglobulin and T-cell receptor gene rearrangements, fusion genes, or aberrantly expressed genes, single nucleotide mutations are considered one of the MRD markers that reflect the malignant cell clone.

METHODS

We compared the quantity of mutant genes by allele-specific quantitative polymerase chain reaction (AS-qPCR) for single nucleotide mutations (TP53 410T>A and PTPN11 1508G>A) with the percentage of autologous DNA by short tandem repeat (STR)-PCR.

RESULTS

Following HSCT, the quantity of mutant genes detected by AS-qPCR correlated with the percentage of autologous DNA assessed by the STR-PCR. Moreover, mutant DNAs were detected at a quantifiable level before relapse, whereas the percentage of autologous DNA was less than 5%, that is, complete chimerism.

CONCLUSIONS

The AS-qPCR approach for single nucleotide mutations was accurate and highly sensitive for monitoring pre-transplantation as well as post-transplantation MRD. AS-qPCR for single nucleotide mutation is suitable for monitoring MRD in patients who lack previously established MRD markers.