Briana Cox had a malignant skin melanoma removed in 2006 and was assured by her doctors that the cancer had not spread and all her margins were clear.
The Phoenix police detective went on to have a son David, now 3, and became again pregnant with her daughter Addison.
But just two months after the baby was born, in June 2011, Cox had a seizure and collapsed during a run. Scans revealed her brain and other parts of her body were riddled with advanced cancer.
And when four dark bumps appeared on baby Addison's forehead in September, she too was diagnosed with the same stage-four melanoma.
Cox died in February at the age of 33, but her last wish was to tell her family's private, but painful story to help others better understand the dangers of the disease.
Her doctors were baffled by this medical anomaly -- Cox's cancer cells had metastasized during her pregnancy and crossed the placenta to her developing fetus.
"It was like running into a brick wall," said James Cox, who was in the Azores serving in the U.S. Air Force when his wife was diagnosed. "It knocks the wind out of you. It was like being punched in the chest. And when Addison was, it was like being ejected from a car. You wonder, what's next?"
The phenomenon has only been recorded "a handful of times" in medical literature, according to Dr. Pooja Hingorani, a pediatric oncologist who is now treating Addison at Phoenix Children's Hospital.
"All cancer can happen in pregnancy," she said. "But melanoma is the most common cancer to pass through the placenta from the mother."
About 30 percent of all mother-to-fetus cancers are melanoma, according to Hingorani, who said she has only seen four to five cases ever.
"When it is in the blood stream, it can go everywhere," she said.
Melanoma is a virulent form of skin cancer that begins in the cells that make the pigment melanin, but it can also begin in the eyes or intestines. According to the National Cancer Institute, about 76,000 new cases are diagnosed each year and 9,100 die of the disease.
Sun exposure is thought to be one of the causes of melanoma. Any suspicious mole that appears on the skin should be examined, especially those that continue to grow or a previous mole that changes color or is not uniform in size. Ulceration and bleeding are also warning signs.
"If you have skin lesions, get referred to a dermatologist," said Hingorani. "We probably miss a lot of patients unless they have advanced disease."
Hingorani said cancer among women of childbearing age is on the rise, and those who are pregnant, should tell their doctors.
"After the birth, the placenta needs to be examined carefully," she said. "It's hard to say if we would have picked it up at birth, if Addison would have had a less extent of disease."
The prognosis for the now 9-month-old is dire. At best, Addison's life expectancy is about two years.
Her cancer is similar to her mother's -- in the brain, shoulder, lungs, kidney, liver, leg, and even the back of her tongue, according to the Arizona Republic, which first reported the story.
"Bri went through the emotions of my baby, my fault, but everyone told her it's not her fault," her husband told the paper. "No one took better care of themselves than her."
Briana's co-workers in the Phoenix Police Department are running a fundraiser March 3 to help the family with escalating expenses.
"Briana and I worked together for seven years and her personality was such that she did things in her own time," Det. Sarah Gasper. "She made the comment that if someone else needs help more than I do, I can help them. That's how she looked at her job -- she helped the public."
Addison's experimental chemotherapy costs about $130 a week and there have been deductibles, co-pays and travel expenses.