The sister of missing Manic Street Preachers guitarist Richey Edwards and parents of Madeleine McCann have joined 450 others in a run for missing people.
The event, held in London's Hyde Park, has already raised £20,000 for Missing People, a charity supporting families of people who have disappeared.
Rachael Elias, 40, of Blackwood, South Wales, said she still hoped Mr Edwards, missing since 1995, would be found.
She said: "I am running it for my brother and to support this charity."
Ms Elias continued: "They have been a tremendous source of strength over the last 15 years.
"He was legally declared dead in November 2008, but there is no certainty over the loss, there is that hope.
"Until he is found alive or dead we will always have hope."
Mr Edwards has not been seen since his car was discovered near the River Severn in Wales when he was 27 years old.
Kate and Gerry McCann, from Rothley in Leicestershire, ran wearing T-shirts bearing an image of their daughter under the slogan: "Don't give up on me."
Madeleine McCann went missing in 2007 on a family holiday in Portugal.
Mrs McCann, 42, said: "Gerry and I know the pain that having Madeleine missing has caused us, but sadly we are not alone.
"There are thousands of families across the UK waiting for news.
"That's why Missing People provides support for missing children, vulnerable adults and families left behind, and we want to do all we can to help them."
Martin Houghton-Brown, chief executive of Missing People, said: "It is a really important day.
"It is not just about the families who have someone missing, it is about Britain as a whole recognising that this is an issue that can affect anybody.
"When somebody goes missing the friends and family need a huge amount of support. Missing People is there 24 hours a day, seven days a week."
[Originally published: news.bbc.co.uk, 13 March 2010]