>>> we have a health news story to report tonight that's getting a lot of attention and doctors hope it can be a turning point in the fight against one of the most prevalent forms of skin cancer. this is just one case, but it could be a major clue in how to use the body's immune system to take on melanoma which strikes more than 76,000 americans every year. we get details tonight from our chief science correspondent.
>> she was a 42-year-old mother of three living with a death sentence. end stage melanoma throughout her body meant she was out of options.
>> it went into the right lung, lymph nodes, the spleen. and at that point the key mow didn't work.
>> rick wilke also had stage 4 melanoma. both were taking a drug which treats advanced skin cancer by prompting the body's immune system to destroy it. when it works the results can be sensational.
>> the nurses --
>> everybody was jumping up and down.
>> everybody came into this tiny little room and gave us the good news.
>> the drug only works in 10% to 20% of patients. when valerie esposito took it, her cancer continued to spread. one tumor was pushing up against her spine causing severe pain. doctors used radiation to treat it.
>> look at what happens three months after the radiation.
>> what happened then was astonishing. these dark spots which is where cancer spread to the spleen, disappeared, along with other tumors throughout her body.
>> we're very excited about this result because we treated just one tumor with radiation therapy in this patient. and as a result, distant tumors regressed.
>> dr. jed and his team at memorial sloan kettering kept other samples from esposito and believe they know exactly how the radiation prompted the immune system to destroy the other tumors.
>> it felt like a battle that i wasn't going to win. it definitely was a miracle.
>> and now a nationwide clinical trial is getting under way with the hope that this new understanding could help thousands or melanoma patients have a brighter prognosis.
