London, Sep 5 (IANS): Researchers have discovered new genes and natural toxins that offer hope for millions of cancer patients who are unresponsive to chemotherapy.

A team from Queen Mary University of London have identified two new genes that cause head and neck cancer patients to be resistant to chemotherapy.

They found that silencing either gene can make cancer cells previously unresponsive to chemotherapy subsequently respond to it.

"Unfortunately, there are lots of people out there who do not respond to chemotherapy or radiation. But our study has shown that in head and neck cancers at least it is these two particular genes that could be behind this, which can then be targeted to fight against chemoresistance," said Muy-Teck Teh, senior author of the study from the University.

The two genes actively 'work' in most human cancer types, meaning the findings could potentially extend to other cancers with elevated levels of the genes.

There are 12,422 new cases of head and neck cancer each year, and the overall 5-year survival rate of patients with advanced head and neck squamous cell carcinoma (HNSCC) is less than 25 per cent.

The major cause of poor survival rates of HNSCC is because of treatment failure that stems from resistance to chemotherapy.

In the study, the scientists first used a method known as data mining to identify genes that may be affecting tumour responsiveness to drug therapy.

They tested 28 genes on 12 strains of chemo-resistant cancer cell lines, finding 4 'significant' genes that were particularly responsive that they then investigated further and tested multidrug-resistance.

"These results are a promising step towards cancer patients in the future receiving personalised treatment based on their genes and tumour type that give them a better survival rate and treatment outcome," Teh said.