The Dallas scientists were concentrating on biological factors while Thorpe's lab in England focused on chemistry and protein engineering. In 1991 he joined the UT Southwestern team. He now holds the Serena S. Simmons Distinguished Chair in Cancer Immunopharmacology. Soon after arriving in Dallas, however, Thorpe decided he wanted to focus on solid tumors, essentially all malignancies except lymphomas and leukemias. To his inquisitive mind, solid tumors were more of a challenge.
Solid tumors are more deadly and more common, especially non-small cell lung cancer.
Solid tumors also are more difficult to kill. They are less permeable and less accessible to intravenously administered drugs, such as chemotherapy and immunotoxins. Cancer cells are chameleons. They change form, or mutate, so a drug that may kill off some of the malignancy often loses its effectiveness. Thorpe decided to find a way around these obstacles, and he remembers when the idea struck him to coagulate the tumor's blood supply.