"I didn't have a choice," said Robinson. "He was my boy and he changed my life fundamentally. Some people continue on the same course. For me, it was life-defining."
In 2010, he set up Two Million Dogs, believing that dogs, who live in the same environment as humans, can give clues to why humans get cancer.
"They are like the canary in the coal mines -- we drink the same water," said Robinson.
Today, Robinson is still homeless and jobless, but a tireless advocate for comparative research.
The organization he founded for sponsors is called "Puppy-Up Walks" -- similar to the fundraising efforts for the Susan G. Komen for the Cure foundation and hosted in in 40 cities around the country.
Sadly, Robinson's Great Pyrenees, Murphy, died of nasal cancer in June. And now, the man who never thought he would fall in love with a dog has a new puppy, Indiana.
"Before," he said of Malcolm, "I didn't know I could have a spiritual connection with an animal."