A man in England is among the first in the world to receive a personalised vaccine, which scientists hope will protect against skin cancer.
Stevenage man Steve Young, 52, is one of many skin cancer patients taking part in the clinical trial, after having a melanoma tumour removed from his scalp last year.
About 70 skin cancer patients, who've had a high-risk melanoma surgically removed in the last 12 weeks, will receive the mRNA-41567 (V940) vaccine. Some will get a placebo jab instead.
Speaking to the BBC, Young said the trial gave him a chance to feel like he was fighting back against a "potential unseen enemy".
Scans showed he was clear of cancer, but there was a chance cancerous cells remained undetected, he added.
"I actually had this chance to get involved in putting on some boxing gloves and squaring up to it."
Doctors at the University College London are giving the vaccine to patients, alongside immunotherapy drug pembrolizumab (Keytruda).
They hope to stop cancers from returning.
University College London investigator Dr Heather Shaw said the "custom-built" mRNA vaccines could be used to treat other cancers, such as lung, bladder or kidney.
There's hope the new therapy could be a "gamechanger", especially due to its "relatively tolerable side-effects", Dr Shaw said.
The new treatments are based on the same technology as COVID-19 mRNA vaccines, but each vaccine is personalised to each patient.
It essentially reprogrammes a patient's immune system to recognise and destroy any remaining cancer cells that surgery or chemotherapy cannot kill.
The mRNA shot provides genetic instructions for the body to make proteins or antibodies, which can identify unique cancer cell markers (antigens).
"You couldn't give this to the next patient in the line because you wouldn't expect it to work," said Dr Shaw.
Pharmaceutical companies Moderna and Merck Sharp developed the new treatment, which is being trialled on patients in a number of countries, including Australia.
Young said it was a "massive shock" to find out the lump growing on his scalp for several years was cancerous.
"My dad died of emphysema when he was 57 and I actually thought 'I'm going to die younger than my dad'," he told the BBC.
Data from Phase II of the trial, released in December, found that patients who got the mRNA vaccine with Keytruda had a 49 percent lower risk of having their cancer return within three years compared to placebo.
Signs of skin cancer can include an asymmetrical mole, a mole with blurry or jagged edges, uneven colouration, changing diameter, or itching, bleeding or crustiness.
