Real-time PCR comparison of gene expression profiles in parallel bone marrow and peripheral blood samples in acute myeloid leukaemia.

AIMS: Microarray expression studies have identified genes signatures (Indicator genes) in bone marrow that provide more precise prognostication in haematological malignancy. It would be beneficial if these diagnostic signatures could be measured in peripheral blood. The aim of the present study was to determine the degree of correspondence of gene expression for a set of Indicator genes between bone marrow and peripheral blood in acute myeloid leukaemia (AML). METHODS: Parallel bone marrow aspirate and peripheral blood samples were obtained from 19 patients diagnosed with AML and mononuclear cells isolated from both sample types. mRNA was globally amplified using a polyA RT-PCR method and the expression of 15 AML Indicator genes, identified from previous microarray studies, measured by real-time PCR. All values were normalised to the mean expression of three housekeeping genes (IF2-beta, GAP and RbS9) and were statistically compared using SPSS software. RESULTS: There was no statistically significant difference in expression between BM and PB for ten of the genes (leptin receptor, CD33, adipsin, proteoglycan 1, MB-1, cyclin D3, hSNF2b, proteasome iota, HKrT-1 and E2A) indicating possible use in monitoring disease activity in PB samples; whilst c-myb, HOX A9, LYN, cystatin c and LTC4s showed significantly different expression between BM & PB. CONCLUSION: These results indicate possible use of the method for monitoring AML in peripheral blood by real-time PCR measurement of Indicator genes. In addition, initial use of polyA PCR facilitates translation to very small clinical samples, including fractionated cell populations, of particular importance for monitoring of haematological malignancy.