NEW DELHI: An international team of researchers has discovered a new method to fight cancers that no longer respond to treatment.

The team led by Israel's Weizmann Institute of Science used mutations that make tumours drug-resistant, Xinhua news agency reported.

One of the biggest challenges in cancer care is when a therapy stops working.

In many metastatic cancers, drugs that initially work lose their effect over time as cancer cells mutate and continue to grow.

The new study, published in the journal Cancer Discovery, proposed a new way to confront cancer resistance: harnessing the very mutations that make tumours resistant in order to fight the cancer.

The team introduced a computational tool called SpotNeoMet.

It identifies therapy-resistant mutations common to many patients.

These mutations produce tiny protein fragments called neo-antigens, which appear only on cancer cells.

These shared neo-antigens may provide the basis for new immunotherapy approaches that prompt the immune system to selectively target cancer cells.

"Our research demonstrates a broad principle that may change the way we think about treatment-resistant cancer," said Prof. Yardena Samuels at the Weizmann.

"The same mutations that allow a tumour to evade a drug can, through precise immunotherapy, become the cancer's weak point. Unlike 'boutique' immunotherapies that must be tailored to each individual patient, these therapies could be suitable for large groups of patients," Samuels added.

The researchers tested their approach on metastatic prostate cancer, a disease where most patients eventually become resistant to standard treatments.

They identified three neo-antigens that showed promising results in lab experiments and in mouse models.

The researchers said the approach differs from highly personalised therapies because it targets resistance mutations shared by many patients. This allows the same treatment to be applied more broadly to people with treatment-resistant cancers.