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Improving the Quality of Cancer Clinical Trials: Workshop Summary
more inclined to participate in clinical research. This could be done by developing practice environments that encourage and reward imagers to engage in research.
Dr. Piwnica-Worms concluded by reiterating the caveats of imaging that were described by other speakers. These caveats include that imaging may demonstrate that a target is being hit or confirm the expected mechanism of action, but it alone does not imply clinical benefit. He acknowledged the regulatory and financial barriers linked to imaging biomarker validation. These barriers hinder sponsors from running clinical trials in this country. Many imaging trials are moving overseas, he noted, and this poses a threat to the U.S. trial infrastructure.
Use of Proteomics/Genomics to Assign Therapy in Lung Cancer
Dr. Mendelsohn summarized his group’s discussion on the use of proteomics and genomics to assign therapy in lung cancer. This group’s discussion was focused on the presentations by Drs. David Carbone from Vanderbilt University and Mark Kris and William Pao of MSKCC. Dr. Carbone used the MALDI (matrix assisted laser desorption/ionization) mass spectrometry system to detect protein signatures associated with longer survival in 139 advanced lung cancer patients following treatment with tyrosine kinase inhibitors gefitinib or erlotinib. In this retrospective study, he found the elevated production of eight key proteins in blood serum linked to longer survival. A second retrospective study in a different group of lung cancer patients found that the eight proteins did not correlate with longer survival in patients treated with standard chemotherapy, or surgery and radiation. This suggests that the eight-protein signature specifically predicts longer survival following treatment with a tyrosine kinase inhibitor and not merely in those patients likely to survive longer no matter what treatment they receive. He plans to do a prospective study on the usefulness of the protein signature in predicting lung cancer patients who will respond best to tyrosine kinase inhibitor treatments. Dr. Carbone also has used two-dimensional gel electrophoresis to find a more complex protein pattern, encompassing more than 1,000 proteins, that is present in the lung biopsies of cancer patients, but not in normal lung tissue biopsies. He is currently looking for candidate diagnostic markers among these proteins.
Drs. Kris and Pao reported that EGFR is overexpressed in 45 percent of non-small cell lung cancers (NSCLCs), as measured by immunohistochemistry. Studies done by Dr. Pao and others (Lynch et al., 2004; Paez et