Carol Witcher of Newton County, Georgia says her 9-year-old boxer, Floyd Henry, saved her life. She says the dog began to sniff her breath and nose then he pushed against her breast. That prompted Carol to do a self-exam on her breast and she found a lump the size of a baseball. It turns out she had stage 3 breast cancer. Researchers in are studying whether specially-trained dogs can detect certain cancers. The theory is that the dogs can smell certain chemical changes in the body linked to the disease.