My 20-year-old son Charles (Trey) Rood III is a junior at the University of Georgia. He was diagnosed with stage III melanoma when he was just 15 years old.

Trey waged many battles in his long war against cancer until two years ago when, as a stage IV melanoma patient, he was treated with adoptive T-cell therapy, or TIL therapy, at MD Anderson.

Soon after, we saw signs of improvement suggesting that Trey was finally...