Lassie becomes despondent after realizing Jeff has cancer instead of Porky.

California Foundation Trains Canine Cancer Sniffers
Labrador Retrievers and Portuguese Water Dogs Can Smell Cancer on People's Breath

Hopes for early detection of lung and breast cancer has scampered forward with the announcement of dogs being trained to smell cancer on people's breath. The research is being conducted at the Pine Street Foundation in San Anselmo, CA. Apparently cancer cells release molecules that are different from those of healthy cells. Dogs with their highly tuned sense of smell are able to differentiate the different types of cells. "The dogs have learned to sit or lie down in front of cancer patient samples and to ignore control samples through the method of food reward," a spokesman said.