New research has begun to unravel the mystery of why a particular form of leukaemia in infants has defied efforts to improve outcomes, despite significant improvements in treating older children.
Baby holding a hand. Free image via Pixabay
Scientists from the Wellcome Sanger Institute, Great Ormond Street Hospital, Newcastle University and their collaborators found subtle differences in the cell type that causes B acute lymphoblastic leukaemia (B-ALL) that may help to explain why some cases are more severe than others.
The study, published in Nature Medicine, focused on the majority of infant B-ALL cases caused by changes to the KMT2A gene. The findings provide a number of promising drug targets, raising hopes that effective treatments for infant B-ALL may be developed in the future.
Acute lymphoblastic leukaemia (ALL) can take various forms, depending on the cell type involved. These cancers occur when cells malfunction as they develop from haematopoietic stem cells to mature blood cells. In the case of B-ALL, disease arises from a type of immune cell called B lymphocytes, more commonly known as B cells.
B-ALL in children was once a universally fatal disease that is now curable in the majority of cases1. An exception is B-ALL in children below one year of age, where treatment is successful in less than 50 per cent of cases, with no significant improvement in the last two decades. Treatments that are proven in tackling other forms of leukaemia, such as bone marrow transplants, have proved ineffective against infant B-ALL. It is currently treated with strong chemotherapy, which can be hard for the patient to endure even if they are cured.
In this paper, researchers set out to study KMT2A-rearranged infant B-ALL by comparing cancer cells to normal human blood cells. Gene expression data from 1,665 childhood leukaemia cases was referenced against single-cell mRNA data from around 60,000 normal fetal bone marrow cells2.
Analysis found that infant B-ALL exhibited distinct cellular signals with a notable contribution from early lymphocyte precursors (ELPs)3, an immature immune cell type that normally develops into B cells.
Source: Sanger Institute