Right Under Our Noses

FOR AGES,THE SENSE OF SMELL HAS BEEN UNDERESTIMATED AND POORLY UNDERSTOOD. NOW SCIENTISTS ARE TRYING TO CRACK THE CODE OF HOW IT WORKS—AND CREATE ROBOTS THAT CAN SNIFF OUT THE WORLD'S SECRETS LIKE A DOG.

- Sara Harrison

THE DOGS STILL MAKE ANDREAS MERSHIN ANGRY. "I MEAN, I LOVE DOGS," SAYS THE GREEK-RUSSIAN SCIENTIST, IN HIS OFFICE AT M.I.T. "BUT THE DOGS ARE SLAPPING ME IN THE FACE."

He pulls up a video to show me what he means. In it, a black dog named Lucy approaches a series of six stations, each separated by a small barrier. At every one, a glass cup of human urine with a screened lid sits at the level of the animal’s nose. Lucy takes a brief sniff of each sample, sometimes digging her snout in to get a better whiff. She is performing a kind of diagnostic test: searching for the telltale scent of prostate cancer, which, it turns out, leaves a volatile, discernible signature in a man’s pee. Discernible if you’re a dog, anyway. When Lucy finds what she’s looking for, she sits down and receives a treat.

Among humans—whose toolmaking prowess has given the world self-driving suitcases and reusable rocket boosters— prostate cancer is notoriously difficult to detect. The prevailing method is to check a patient’s blood for elevated levels of a protein called prostate-specific antigen. But the test has a miserable track record. The scientist who first discovered PSA has described the test as “hardly more effective than a coin toss.” A false positive can lead to a prostate biopsy, a harrowing procedure that involves inserting a large, hollow needle through the wall of the rectum to retrieve a tissue sample from the prostate itself.

Properly trained dogs, on the other hand, can detect prostate cancer with better than 90 percent accuracy, and with sleek, tailwagging efficiency. In the video, Lucy works her way through six samples in just a couple of minutes. This drives Mershin up the wall. “We have $100 million worth of equipment downstairs. And the dog can beat me?” he says. “That is pissing me off.”