You are releasing a powerful chemical trail that can identify
early signs of cancer and other diseases. Welcome to medicine's
new era of smell diagnosis  Maarten de Groot  Claire Guest,
whose breast cancer was detected by her pet, Daisy, before a
core needle biopsy  Maarten de Groot   In october 2012, Billy
Boyle -- an electronics engineer -- took his girlfriend Kate to
Addenbrooke's hospital in Cambridge, when she complained of a
stomach ache. Eight hours later, she was having emergency
surgery to remove the large, metastatic tumour that was choking
her colon. "Her cancer was advanced, it had already spread to
her liver," Boyle says, leaning forward on a large wooden table
in his office at Cambridge science park on a rainy April day in
2013. "Her chances of survival were five percent."   After the
surgery, Boyle tried to think of any early symptoms they might
have overlooked, but came up blank. Kate, 34, had been healthy
enough to travel around the United States, fundraising for her
charity, just days earlie