The dogs who may offer hope of early cancer detection
Claire Guest is the chief executive of Medical Detection Dogs, an organisation that trains dogs to identify human disease by odour.
The charity is doing research into whether dogs can be used to sniff out the presence of cancer in its early stages. They also work with medical assistance dogs - dogs who help their owners manage their medical conditions.
In 2009 Guest herself discovered she had breast cancer. She says it was her dog, Daisy, who first alerted her that something was wrong.
Video journalist: Natalie Morton