Dame Tessa Jowell was given a standing ovation after making an emotional plea for more cancer treatments to be made available through the NHS months before her death.
In the process, he said, "she gave hope and opportunity to hundreds of thousands of children".
Sarah Lindsell, chief executive of the Brain Tumour Charity, said: "Tessa Jowell's courage and honesty in speaking about her brain tumour diagnosis, coupled with her fierce determination to improve the lives of others affected by the disease, has already brought hope to an often-forgotten community of patient and families".
"All of us, for longer".
Tony Blair, of whom she was a big supporter, said Dame Tessa was "the wisest of counsellors, the most loyal and supportive of colleagues, and the best of friends".
"If anyone wants to know what politics can achieve they can just look at her life and how she lived it, and how she ended it as a testimony to all that's best in politics". The family said the funeral would be small and private, but a memorial open to all would be held later.
David Beckham, who was an ambassador for the London 2012 bid, wrote on Instagram: "Dame Tessa was a passionate and fantastic woman in so many different ways and will be missed by so many".
Four-time Olympic gold medal-winning rower Matthew Pinsent said: "RIP Tessa Jowell - absolutely central to the effort to win and stage the Olympics and Paralympics in 2012".
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Sarah Lindsell, CEO of the Brain Tumour Charity, said the charity had started working with "wonderful ambassador" Dame Tessa towards the end of previous year, and she praised her campaigning for cancer patients.
"I can say with confidence she embraced everyone, survivors and families of the dead", she said.
Former prime minister David Cameron tweeted that he was "devastated by the news".
Elsewhere, former acting Labour Leader Harriet Harman described Dame Tessa as "no softie", saying: "Tessa was my MP neighbour for 23 years, always courteous and polite with local agencies, hospitals and schools".
Dame Tessa, a former social worker, first stood for Parliament in a 1978 by-election in Ilford North on the Essex-London border.
The former spokesman of Tony Blair told Nick Robinson on BBC The Andrew Marr Show his daughter was "weeping" as the news of Dame Tessa Jowell's death arrived on Saturday. She lost to her Conservative rival and was defeated again the following year.
When Jowell was culture secretary, she helped secure the 2012 Olympics for London. In 1997, she was one of the 101 female Labour MPs on the benches following the party's landslide victory.
David Cameron shared a picture of himself and Dame Tessa recreating the Beatles' Abbey Road cover, writing: "Devastated that Tessa Jowell has passed away after her incredibly courageous fight". But it was her work on the Olympics that made her known to the general public.
"Passionate, warm and empathetic, she saw the best in everyone and won respect and affection across the political spectrum".