Gene found to defend against acute leukaemia

Australian scientists have discovered that a gene called PHF6 plays a powerful role in protecting against blood cancer, revealing in the journal Blood how a breakdown in the gene’s function could accelerate the development of T cell acute lymphoblastic leukaemia (T-ALL).

Understanding how potential ‘tumour suppressor genes’ work is important for T-ALL because new prevention and treatment strategies are urgently needed, with half of all adult patients with this cancer not surviving beyond five years. Now, a research team led by Melbourne’s Walter and Eliza Hall Institute (WEHI) has provided the first direct evidence that PHF6 is a tumour suppressor gene.

“We discovered how PHF6 was important for limiting cell division,” said Dr Helen McRae, a co-leader of the study. “This is significant because the overproduction of cells is a hallmark of cancer. Our study showed that without the tumour suppressing function of PHF6, the early stages of normal blood development were disrupted which could potentially explain how PHF6 mutations lead to leukaemia.”

The study also found that PHF6 was important for regulating the expression of other genes, said Dr McRae, who noted, “A loss of PHF6 conspires with other genetic mutations found in blood cancer patients. We saw this to be the case with a gene called TLX3, that is overexpressed in leukaemia cells.”

Co-leader Associate Professor Tim Thomas said that in order to improve early diagnosis and treatment of cancers, researchers needed to forensically investigate genetic mutations to better understand their impact because not all mutations played a role in driving or maintaining disease.

“Large-scale sequencing efforts have pinpointed more than 100 genes frequently mutated in T-ALL,” he said. “For this information to be useful for improving diagnosis and treatment, investigating the contribution of these genes to disease development and progression is essential.”

Dr McRae said PHF6 is well worth exploring because previous studies have shown the gene is the fifth most common mutation in T cell leukaemias. Mutations in PHF6 generally occur during a patient’s lifetime due to environmental factors and errors in the DNA repair process. In some rare cases, people are born with these mutations, which result in Borjeson-Forssman-Lehmann intellectual disability syndrome (BFLS). It is important to note that a subset of BFLS patients develop leukaemia early in life.

“It is our job as cancer researchers to determine which mutated gene ‘suspects’ are actually ‘culprits’ for driving disease so that we can carry this important information forward in our mission to combat disease,” Dr MacRae said. “This is why it is so exciting to have identified PHF6’s tumour suppressor function and establish that loss of PHF6 function drives and maintains leukaemia.”

The team’s findings have surfaced the need to focus on finding new ways to restore the function of the gene in adult patients with mutated PHF6. They have also highlighted the importance of closely monitoring infants born without PHF6 functioning to ensure that any cancer is detected early.

Image credit: ©stock.adobe.com/au/Rido

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