The polymerase chain reaction (PCR) has a role in monitoring responses to treatment of children with acute lymphoblastic leukaemia (ALL), according to a report in the Journal of Clinical Oncology.


Acute lymphoblastic leukaemia is the most common paediatric cancer. Being able to monitor minimal residual disease (MRD) would help physicians to stratify patients, carry out individual risk-directed treatment, and track their progress. A team of Italian researchers looked into measuring blast clearance from bone marrow during and after induction therapy, to see if this could identify those individuals who are most at risk of relapse.

The researchers used real-time quantitative PCR (qPCR) to measure blast clearance post-induction therapy in 110 children and adolescents with acute lymphoblastic leukaemia, categorising them as negative, low positive or high positive.

The risk of relapse was significantly different in the three groups of patients – for patients testing negative, the relapse risk was only 9%, rising to 35% for the low positive group and 83% for the high positive group. As two thirds of the positive cases were spotted within 4 months of induction-consolidation therapy, this could be the best and most cost-effective period for monitoring patients, especially those individuals in whom disease hadn’t initially been cleared.