Arizona Baby Who Got Melanoma in Womb Is Still Thriving

April 10, 2013— -- Addison Cox, the Phoenix girl who mysteriously contracted her mother's deadly melanoma while still in the womb, has surprised doctors and will soon celebrate her 2nd birthday.

Her mother, Phoenix police detective Briana Cox, died last year of cancer that had metastasized during her pregnancy. She was only 33.

In a rare and unexplained medical mystery, Cox's cancer cells had crossed the placenta to her developing fetus.

Addison was just 6 weeks old when doctors found tumors had spread throughout her body. Her family was told she would likely not survive much beyond a year.

"Her original diagnosis was 12 to 18 months," James Cox, told ABCNews.com. "She turns 2 in May."

"We sure are pleased," he said. "Basically our family has gotten so much support from each other and friends. ... The local church took us under their wing and my co-workers have been so kind to all of us."

Addison has a 4-year-old biological brother who has been in counseling since his mother died.

"He still thinks about his mother and misses her," said Cox, 37. "But talking to a 4-year-old kid about anything can be difficult."

Addison also has two teenage stepbrothers. Cox's mother, who is from Texas, has been living with the family to help out for the last nearly two years.

The cancer has affected the child's brain, shoulder, lungs, kidney, liver, leg, and even the back of her tongue. She has had chemotherapy, radiation and brain surgeries at Phoenix Children's Hospital, which is hosting a telethon to benefit the family.

The toddler has been on chemotherapy for 20 months and has undergone radiation. A month ago she had two brain surgeries four days apart.

A fundraiser by the police department where Briana Cox worked has helped the family deal with their financial needs. "Most has been covered by medical insurance, but it's the cost of day-to-day life that really hammers us," said Cox.

So far, Addison has progressed well, understanding speech and saying a few words, like any child her age, according to her father.

"That gives you a lot to look forward to and know she's still doing this well, it just kind of keeps you going," said James.

Today Phoenix Children's Hospital is hosting a telethon in coordination with ABC 15.

"One hundred percent of the proceeds raised will have a direct impact on care, along with critical programs services provided to patients and families," said hospital spokeswoman Stacy Dillier.

Addison's mother 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.

Briana Cox went on to have a son David, now 4, and again became 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 of 2012, 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 husband was in the Azores, serving in the U.S. Air Force, when his wife was diagnosed. Today Cox is in emergency management.