Genomic quantitative real-time PCR proves residual disease positivity in more than 30% samples with negative mRNA-based qRT-PCR in Chronic Myeloid Leukemia

Ilaria Stefania Pagani, Orietta Spinelli, Elia Mattarucchi, Cristina Pirrone, Diana Pigni, Elisabetta Amelotti, Silvia Lilliu, Chiara Boroni, Tamara Intermesoli, Ursula Giussani, Luigi Caimi, Federica Bolda, Renata Baffelli, Eleonora Candi, Francesco Pasquali, Francesco Lo Curto, Arnalda Lanfranchi, Fulvio Porta, Alessandro Rambaldi, Giovanni Porta

Research output: Contribution to journalArticle

Abstract

Imatinib mesylate (IM) is the first line therapy against Chronic Myeloid Leukemia, effectively prolonging overall survival. Because discontinuation of treatment is associated with relapse, IM is required indefinitely to maintain operational cure. To assess minimal residual disease, cytogenetic analysis is insensitive in a high background of normal lymphocytes. The qRT-PCR provides highly sensitive detection of BCR-ABL1 transcripts, but mRNA levels are not directly related to the number of leukemic cells, and undetectable results are difficult to interpret. We developed a sensitive approach to detect the number of leukemic cells by a genomic DNA (gDNA) Q-PCR assay based on the break-point sequence, with a formula to calculate the number of Ph-positive cells. We monitored 8 CML patients treated with IM for more than 8 years. We tested each samples by patient specific gDNA Q-PCR in parallel by the conventional techniques. In all samples positive for chimeric transcripts we showed corresponding chimeric gDNA by Q-PCR, and in 32.8% (42/128) of samples with undetectable levels of mRNA we detected the persistence of leukemic cells. The gDNA Q-PCR assay could be a new diagnostic tool used in parallel to conventional techniques to support the clinician's decision to vary or to STOP IM therapy.

Original languageEnglish
Pages (from-to)510-521
Number of pages12
JournalOncoscience
Volume1
Issue number7
DOIs
Publication statusPublished - 2014

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Keywords

  • Chronic myeloid leukemia
  • DNA Q-PCR
  • Leukemic stem cells
  • Minimal residual disease
  • Stop imatinib

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

Pagani, I. S., Spinelli, O., Mattarucchi, E., Pirrone, C., Pigni, D., Amelotti, E., Lilliu, S., Boroni, C., Intermesoli, T., Giussani, U., Caimi, L., Bolda, F., Baffelli, R., Candi, E., Pasquali, F., Lo Curto, F., Lanfranchi, A., Porta, F., Rambaldi, A., & Porta, G. (2014). Genomic quantitative real-time PCR proves residual disease positivity in more than 30% samples with negative mRNA-based qRT-PCR in Chronic Myeloid Leukemia. Oncoscience, 1(7), 510-521. https://doi.org/10.18632/oncoscience.65