Andy Stapleton

Andrew Stapleton is a scientist and science communicator based in Adelaide. He is a presenter and producer of the popular podcast Publish, Perish or Podcast, posts weekly science articles on his website and has written for Australasian Science, Cosmos Magazine and ScienceAlert.

Mutations in this gene are responsible for half of human cancers.

Credit: iStock

Nearly 40 years ago, a gene was discovered which laid the foundations of our understanding of how our own bodies stop rogue cells turning into cancerous ones. 

The gene, called p53, regulates how cells react to various stresses and can instruct an out of control cell to stop multiplying or die. 

It is so effective at doing so, it has earned the name of “super tumour suppressor gene”.

Even though we’ve known about this gene for some time, exactly how it performs its amazing anti-cancer functions remained a mystery.

For the first time, Melbourne scientists have found that a specific group of genes that work in the body’s normal DNA repair process, are vital to p53’s effectiveness in stopping cancer.

“It is defects (mutations) in this gene that’s actually causing 50 per cent of human cancers,” says lead author Dr Ana Janic. “It’s really exciting because we’ve kind of opened the window for many new discoveries in this area”.

Meticulous screening

The researchers meticulously screened more than 300 genes directly regulated by p53 to identify which ones were critical for its tumour-suppressing function.

The research team discovered that the DNA repair gene MLH1 and as well as other related genes are critical to p53’s ability to prevent the development of B-cell lymphomas.

Co-author Associate Professor Marco Herold said, “It was amazing to find that the loss of the DNA repair gene MLH1 prevented p53 from functioning properly, causing the development of lymphoma,” he says. “And when MLH1 was put back into the equation, tumour development was significantly stalled.”

A universal cancer treatment?

Dr Janic says that while the results may take several years to translate into a treatment, it provides a pathway for personalised treatment options for many types of cancer.

“For instance, if a patient has lymphoma with a mutation that disables the DNA repair mechanism, doctors will now know to avoid certain DNA-damaging treatments, like chemotherapy, that may only make the cancer more aggressive,” she said.

The next steps will focus on understanding if the DNA repair process has the same cancer-blocking impact on cancers other than lymphoma, such as colon cancers in which 70 percent are caused by p53 mutations. 

“We are keen to test whether genes involved in the DNA repair process might also play a role in helping p53 to prevent the development of these highly prevalent and, in the case of pancreatic cancer, highly deadly cancers,” says Dr Janic.

The study was published in Nature Medicine.

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