Ashya King is free of brain cancer, his parents say. Brett and Naghmeh King sparked an international manhunt when they removed the five-year-old from Southampton General Hospital against doctors' orders in August last year.
But dad Brett, 51, has told The Sun that Ashya is now free of the disease.
He said: "It's incredible news. We are absolutely delighted. It has justified everything we have gone through because things are working out for Ashya.
"If we had left Ashya with the NHS we don't think he would have survived. We have saved his life."
Mum Naghmeh, 46 added: "We could not sleep before we got this news - now we are so full of hope for the future. We are jumping up and down with joy. It is a miracle we thought we would never see."
Brett and Naghmeh took Ashya abroad to a Prague clinic against doctors' orders for proton beam therapy on a brain tumour which was unavailable on the NHS.
The treatment is said to target cancers more precisely than traditional radiotherapy, with less chance of damaging surrounding tissue.
They believed traditional radiotherapy techniques would 'fry' the five-year-old's brain.
Ashya had 30 rounds of proton beam treatment at the centre which ended in October last year.
He has since gone through months of gruelling physiotherapy in Spain where the family now live.
Last week, Ashya took his first steps unaided and completed a course of intensive daily physiotherapy.
The Kings want to return to the UK with Ashya but fear that British social workers may take him from them again despite assurances from local authority officials will not interfere.
In December last year, Brett claimed he was treated 'like a criminal' when he returned to Britain for the first time after fleeing the country with Ashya.
He claimed Border Force officers had taken his and his older son's passports at Gatwick Airport and held them until two police officers decided the pair could go.