In a Wikipedia entry:
"Upon her return to Canada, Duffin settled in Ottawa where she took on a contract to review a set of slides, which she assumed were to be used in a malpractice suit. She was given no information about the patient, but identified the young woman as suffering from acute myeloblastic leukemia, “the most aggressive leukemia known.” As the slides were from some 5+ years earlier, she assumed the patient as deceased, as that form of leukemia kills usually within two years. Instead, she found that the patient had, after a relapse, gone into remission and was doing well some five years on. Duffin's testimony was to be used by the Vatican to determine whether Marie-Marguerite d'Youville (1701 – 1771) had performed a miracle and was worthy of canonization. According to Duffin, “They never asked me to say this was a miracle. They wanted to know if I had a scientific explanation for why this patient was still alive. I realized they weren’t asking me to endorse their beliefs. They didn’t care if I was a believer or not, they cared about the science"
You can read her own account of that miracle, how she judged the case only through the lens of a microscope. She has also written two books about the medical miracles documented in the different canonizations.
She remains an atheist. Now that is one miracle let us hope for!