On dogs' ability to detect cancers

On dogs' ability to detect tumors:

from-fire-hydrants-to-rescue-work-dogs-perceive-the-world-through-smell

Excerpt:

One of the most amazing things is that accidentally researchers discovered that dogs could detect melanoma. The accident was that there were individual dogs who were persistently smelling something on their owners. When their owners finally went to a doctor and had it checked out it turned out to be a melanoma.

So since that time there's been a budding research program in training dogs to detect various cancers on the breath, in urine, in blood and on the skin. Most of these programs report very high levels of success. Dogs are definitely able to detect whatever it is in the cell that makes it cancerous.