dr. anil potti: and that's the goal, is to... atient with cancer that i'm not just a cancer doctor, i'm here to treat your particular cancer. >> pelley: dr. potti made the breakthrough in the renowned lab of dr. joseph nevins. the nevins lab had built a reputation for important work. dr. nevins saw something in dr. potti, and he chose the young researcher to mentor and support. >> dr. joseph nevins: very bright, very smart individual, very capable. he was a very close colleague to many, many people. >> pelley: and to you. >> nevins: and to me. >> pelley: when dr. potti decoded the genetic makeup of hundreds of tumors, the research created huge computer files of data. that data was the underlying proof in research papers under the names of potti and nevins that were a sensation in the top medical journals. >> kevin coombes: it was going to change medicine. it was going to change how we treat patients. >> pelley: doctors everywhere were eager to save lives with the new discovery. at m.d. anderson cancer center in houston, kevin coom