Coco is a labrador retriever who is being trained to find early stage ovarian cancer. Handler, Dina Zaphiris, clicks and rewards the dog for naturally lingering and becoming more animated at the cancer sample. Coco is a beginning dog, so Dina allows her to go "find" the same sample again for a second reward. Soon after training begins, we never allow the dogs to sniff an old sample. We always switch out the cancer sample (to a NEW PERSON'S sample) for thousands of runs. It is dangerous and detrimental to a dog's training to use only a few samples. That would mean the dogs are being trained to find a few specific samples, instead of learning to find and imprint the "odor of cancer". InSitu is connected with cancer patients all over the world, who graciously help us gather our samples, to train the dogs, and to keep them trained.