Fake news is driving millions to wrongly believe certain everyday items cause cancer, a new poll suggests.
Around 40 per cent of adults believe stress and food additives can lead to cancer - despite there being no convincing evidence for either, reports the Daily Mail.
A third incorrectly fear that electromagnetic frequencies, such as Wi-Fi and X-rays, and eating GM food are other risk factors.
While 19 per cent are convinced microwave ovens and 15 per cent believe drinking from plastic bottles can both cause cancer.
The findings, derived from a survey of 1,330 people in England, also delved into the genuine causes of cancer that many people are oblivious to.
Researchers at University College London and Leeds University found 12 per cent of people are unaware smoking causes cancer.
Two fifths did not know that another risk factor is sunburn, which can triple the risk of skin cancer, scientists claim.
However, belief in mythical causes of cancer did not mean a person was more likely to have risky lifestyle habits.
But those who had better knowledge of proven causes were more likely not to smoke, according to the researchers, who were funded by Cancer Research UK.
Dr Samuel Smith, study co-author, from Leeds, said: "It's worrying to see so many people endorse risk factors for which there is no convincing evidence.
"Compared to past research, it appears the number of people believing in unproven causes of cancer has increased since the start of the century."
This "could be a result of changes to how we access news and information through the internet and social media", he added.
The most popular cancer-causing myths:
42% food additives
35% electromagnetic frequencies
34% GM food
19% microwave ovens
15% drinking from plastic bottles
Dr Smith said: "It's vital to improve public education about the causes of cancer if we want to help people make informed decisions about their lives."
Almost four in ten of all cancers could be avoided by switching to a healthier diet, doing more exercise and giving up smoking.
Of the 360,000 cases diagnosed in 2015, about 135,500 could have been prevented, according to Cancer Research UK.
Experts believe it is further evidence that cancer is largely down to environmental factors - not simply caused by genes or "bad luck".
Clare Hyde, from Cancer Research UK, said: "It's crucial we have the right information to help us separate the wheat from the chaff.
"Smoking, being overweight and overexposure to UV radiation from the sun and sunbeds are the biggest preventable causes of cancer.
"There is no guarantee against getting cancer but by knowing the biggest risk factors we can stack the odds in our favour to help reduce our individual risk of the disease, rather than wasting time worrying about fake news."
Dr Lion Shahab, from UCL, said: "People's beliefs are so important because they have an impact on the lifestyle choices they make.
"Those with better awareness of proven causes of cancer were more likely not to smoke and to eat more fruit and vegetables."
The findings were published in the European Journal of Cancer.