A Labrador retriever could be just as effective at detecting cancer as a laboratory, according to ongoing studies that test dogs' abilities to sniff out cancer in patients.

A recent study found that trained dogs were able to detect prostate cancer in urine with 98 percent accuracy.

Two 3-year-old, female German shepherds were trained at the Italian Ministry of Defense’s Military Veterinary Center using positive reinforcement to recognize prostate cancer-specific volatile organic compounds.

The dogs analyzed more than 400 urine samples, and one dog detected prostate cancer with 100 accuracy, while the second had 98.6 percent accuracy.

However, prostate cancer isn't the only type of cancer dogs have successfully sniffed out.

Man's best friends have also proved their noses can detect breast, ovarian, colon, bladder, skin and lung cancer, typically by smelling breath samples.

Cancer causes the body to release certain organic compounds that dogs can smell but people cannot, and scientists hope that researching the phenomenon will help them one day develop an electronic nose that can detect cancer as dogs' noses can.

With 220 million olfactory cells in their snouts — compared with a mere 50 million in a human nose — it's estimated that a dog's sense of smell is up to a million times better than ours.

In addition to scientific studies, there's also anecdotal evidence that dogs can detect cancer.

Numerous dog owners tell stories of their pets persistently sniffing or nudging an area of their body that later turned out to harbor a tumor.

Such was the case for Maureen Burns, whose 9-year-old collie mix, Max, started acting strangely. Her dog would insistently sniff her breast and back off with what Burns called a "sad look in his eyes."

Burns did have a small lump in her breast, but her mammogram had been clear. But as Max's peculiar behavior persisted, she returned to the doctor and asked for a biopsy.

Doctors were surprised to learn the lump was cancerous.

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