Tea-time News

cup of tea

By: Ali Cranage, Science Writer at the Wellcome Sanger Institute

Hot tea hit the headlines again recently, after a study linking the drinking of scalding beverages to an increased risk of oesophageal (throat) cancer was published.

It is not the first time that such a link has been seen, but the study adds to the weight of evidence. Several studies have now observed the connection, and the WHO lists hot beverages as ‘probably carcinogenic’. The advice is allow hot drinks to cool slightly before drinking them. Adding cold milk does the job too.

Though studies have observed a link between hot drinks and cancer – they can’t prove that one causes the other, and they can’t suggest how it might be happening. To find out for sure, an international team led by researchers at the Sanger Institute and the International Agency for Research on Cancer (IARC) is studying the DNA of 5,000 cancer patients across five continents, as part of the Mutographs project

Tell-tale signs

The team is investigating the DNA changes (or mutations) of different tumours, including oesophageal cancer. Each thing that causes cancer, like tobacco smoke or sunlight, leaves a tell-tale pattern of DNA damage and changes in our cells. About 50 of these ‘mutational signatures’ have been discovered in cancer cells so far, but researchers only know the cause of about half of them.

The team aim to link the DNA changes to specific things in the environment or lifestyles – and so uncover the missing causes of cancer. They are looking in countries across the world with both exceptionally high and exceptionally low rates of cancer.

The recent study in the news was undertaken in North-eastern Iran, where there is a high rate of oesophageal cancer. Tea is typically enjoyed black and scalding hot in Iran, as it is in many countries.

The data from the recent study in Iran will be fed into the mutational signatures project, together with patients DNA samples. Professor Paul Brennan, Head of the Genetic Epidemiology Group at IARC, explained, “By collecting detailed information about people’s lifestyles, habits and environment, we will be gathering clues about what the causes of different cancers might be.”

The team is also investigating oesophageal cancer in other high risk regions including East Africa (Kenya, Tanzania and Malawi), and high risk regions in China and Brazil. Read more about their work on the Mutographs website.

How does something in the environment cause cancer?

Experiments on human cells and tissues, as well as in animals, will be the next steps. This will help them uncover how specific factors cause cancer. The mutational signatures team hope their work will lead to new ways we might prevent cancer across the globe.

We only know the causes of about half of cancer cases. The rest are a mystery. We know that some cancers are more common in some parts of the world than others but we don’t know why.
By looking deep into the DNA of cancers from five continents my team wants to understand what the differences are in these places and, hopefully, identify new and preventable causes.”

Professor Sir Mike Stratton, Principal Investigator and Director of the Wellcome Sanger Institute

Find out more

The project is a Cancer Research UK Grand Challenge, which won £20 million funding in 2017. Find out more:

For more information about the study in Iran, see the Cancer Research UK blog