A woman whose mother died of breast cancer when she was six still has unopened letters her mum left her, saved for the biggest moments of her life.

Amy Leslie, now 22, from north London, lost her mother Danielle in September 2010, just over a year after her grandmother Sylvie Henry died of the same disease.

Before they died, the pair, both professional dancers who ran their own dance school, set up a breast cancer charity, Future Dreams, at the family kitchen table with £100.

"I think they are watching extremely proudly as the charity is achieving what they wanted," she said. "I think they would just be so amazed that it's still going and it has built its own momentum."

Danielle, who was 40, left memory boxes for Amy and her older brothers, Ben and Joe, with gifts and letters for milestones she knew she might not see, including L-plates for their driving tests and messages for birthdays and graduations.

"There was even a key when I turned 18, and it says, 'The key to adulthood'," Amy said.

Sylvie was 62 when she died in July 2009. Amy believes her grandmother was first diagnosed before she was born, and her mother when Amy was one. Both went into remission, but when the cancer came back they launched the charity in 2008.

Amy remembers being confused when her mother lost her hair, but said Danielle wore "funny hats" and dressed up to shield her children from the effects of her treatment.

The pair also staged dance shows to raise money, including one at the Savoy hotel in London.

"There were costumes and all these shows and pink ribbons everywhere," Amy said. "It was almost like the scariness of breast cancer became this fun, amazing charity."

She said she did not fully take in what had happened until years later, and going away to university brought feelings of anger. Seeing a therapist helped, she said, but grief still "comes up in the weirdest ways".

"Sometimes I think, 'I was six, she knew a six-year-old me. What would she think of me today and who I am?'" Amy said.

The charity now runs Future Dreams House, which opened five years ago and offers support to people affected by breast cancer, with some travelling from across the UK to use it.

"The house is like a hug from my mum and my grandma," Amy said.

Because of her family history, Amy, a newly qualified primary school teacher, has already seen doctors about her own breast cancer risk and will start screening at 25. The NHS routinely offers breast screening to women from the age of 50.

She is currently travelling but said she would always be involved with the charity, carrying on its founders' message that no-one should go through breast cancer "alone or without hope".