Bradley Lowery, who got a rousing reception from England fans as he walked out as a mascot for last month's World Cup qualifier against Lithuania, has been picked to be part of a special cell trial.
A message on his campaign's Facebook site warns "it is still in the very early stages but it has shown promise in other types of cancer".
The Sunderland fan, of Blackhall, County Durham, has neuroblastoma - a solid tumour which makes up 8% of the total number of children's cancers in the UK but its cause remains unknown.
The message, apparently written by mother Gemma, reads: "Bradley has had a tough week with treatment and is still not too grand. He is out of hospital now and spending some time with his grandparents.
"Myself and his dad are travelling down to London today to meet with a professor at Great Ormond Street Hospital. Bradley has been accepted on a trial down there and we need to discuss it and sign consent.
"This trial is been funded by Cancer Research UK. It is called CAR T-cell trial. It is only phase one which means it is still in the very early stages but it has shown promise in other types of cancer.
"Bradley has scans next week to see if his current treatment is working, therefore we can not decide what's next until we get the scan results.
"We are hoping and praying for good news, please keep him in your prayers."
The youngster has struck up a friendship with England striker Jermain Defoe and other Black Cats stars who visited him in hospital when he was undergoing life-prolonging treatment.
When Bradley was being treated at the Royal Victoria Infirmary, Newcastle, Defoe gave him a cuddle and the young fan fell asleep in his arms.
Just last week he cancelled a hospital visit from his "best friend" Defoe "as he didn't want him to see him poorly", according to a tweet.
He was cheered up a couple of days later when he felt a little better and Defoe popped by.
Bradley was invited to the BBC Sports Personality Of The Year show and a shot he struck in the warm-up during Sunderland's game against Chelsea was picked as Match Of The Day's goal of the month.