Sofie Degerman, Professor of Biomedical Laboratory Science, Department of Clinical Microbiology and Department of Medical Biosciences, Umeå University, Sweden. Credit: Mattias Pettersson.

New research from Sweden has found DNA patterns can provide key insights into the diagnosis of childhood leukaemia.

The treatment of leukaemia among children could be made more precise with fewer side effects with the help of more accurate methods of diagnosis.

A new study led by Umeå University, Sweden, reveals that analysing methylation patterns in the child’s leukemic cells DNA can enhance risk assessment, helping to ensure that only the children who need the most intensive treatment receive it.

Umeå University’s Professor Sofie Degerman who led the study with participating researchers from several countries, said: “The healthcare system has become much better at saving lives in childhood leukaemia, but the downside of intensive treatments is severe side effects.

“Our results show that DNA methylation analysis may be a viable way to individualise treatment according to the type of leukaemia, with the hope of a better quality of life.”

T-ALL

The subtype of leukaemia that the researchers in Umeå have studied is T-cell acute lymphoblastic leukaemia, T-ALL.

The treatment mainly consists of chemotherapy, administered over two years, and in some cases supplemented with a bone marrow transplant.

Treatment is usually effective; today, almost nine out of ten children diagnosed with T-ALL survive.

The problem is that the treatment causes side effects in the form of nausea, fatigue, susceptibility to infection and hair loss.

In the long term, there is also a risk of heart problems, cognitive impairment, fertility problems and suffering from other cancers.

The risk of relapse varies within the T-ALL patient group, but it is difficult to determine the risk of relapse with today’s methods of diagnosis.

This means that many children receive more demanding treatment for safety’s sake and thus risk more side effects than they might need.

Contribution

One conclusion of the Umeå researchers’ study is that analysis of DNA methylation patterns at diagnosis could contribute to a refined risk stratification to determine which children need which treatment.

The method also identifies those patients who respond poorly to current treatments, and these patients may be in need of new treatment strategies.

Fernanda S Hackenhaar of the Department of Medical Biosciences at Umeå University, who has contributed to the study’s bioinformatic analysis, said: “The method is already used in several hospitals in the diagnosis of brain cancer, and our study shows that it could also be implemented for leukaemia.”

Methylation is an epigenetic process in which chemical groups are added to the DNA sequence, influencing which genes should be expressed and which genes should be silenced. This process occurs in every genome.

The methylation pattern varies between different cell types and contributes to cells unique characteristics and properties.

If the methylation pattern is disrupted, it can contribute to tumour development.

In a way, the DNA methylation pattern acts as a kind of molecular fingerprint, that can provide detailed insights about the properties of the cancer cells.

Dagerman said: “We are continuing our research to investigate the possibility of including DNA methylation analysis in clinical diagnostics for patients with T-ALL.”

Advanced array technology

The current study includes diagnostic leukaemia samples from 348 children with T-cell acute lymphoblastic leukaemia (T-ALL) treated between 2008 and 2020 in the Nordic countries and in the Netherlands.

The researchers have used advanced array technology and bioinformatics to analyse the methylation patterns of approximately 850,000 DNA methylation positions in the genome.

In the study, the researchers have also investigated the gene expression and genetic changes of the leukaemia cells to better understand how leukaemias with different methylation patterns can be treated.

This work will continue in future studies with the aim of further improving treatment strategies.

The study is published in Blood.