A tiny Yorkshire Terrier saved her owner's life after jumping up and down on her chest to alert her to a cancerous lump.Eleven-year-old pooch Bella Boo wouldn't settle in her usual sleeping place and kept trying to lie on Karena Kirk-Drain's chest despite being pushed away.She would lick and bounce on 53-year-old Karena's chest, causing her severe pain.But when she checked her injuries out, she noticed a lump under her skin which doctors confirmed was breast cancer.Karena, of Blackpool, Lancs., then underwent life-saving treatment and believes the disease would have been missed if it wasn’t for Bella-Boo’s actions.