TMC PULSE

t m c » p u l s e | d e c e m b e r 2 0 1 4 6 Journey to the Institute of Medicine three new members of the prestigious organization share their groundbreaking discoveries "P53 is a tumor suppressor, and I would say every tumor somehow figures out how to inactivate p53," said Lozano. "Most of the time it does so by mutating the gene so it's not functional, but sometimes it overproduces inhib- itors of the pathway." Inactivating p53 allows cancerous cells the opportunity to grow freely. A discovery Lozano noted as partic- ularly significant in her research was identifying the importance of MDM2 and MDM4 in inhibiting p53. "The very first mouse model we generated was a model that showed how crucial the relationship between MDM2 and p53 is," said Lozano. The discovery of that relationship represents just one of the many accom- plishments that led to Lozano's IOM membership, an honor she hasn't yet fully absorbed. "It's just now sinking in," said Lozano. "I appreciate that the medi- cal community has highlighted and rewarded our accomplishments with this honor." While the election represents an acknowledgment of the work Lozano has completed thus far in her career, the research process never ends. There is still more to be done to achieve a full understanding of p53 and how it func- tions. "The pathway is a very complex and branched pathway," said Lozano. "We're trying to figure out what the missing pieces are." Among her future goals is charac- terizing a new animal model to under- stand p53 somatic mutations. "All of our models have really revolved around an inherited mutation in p53, so a big part of my lab now is moving towards generating a somatic mutation of p53," said Lozano. "There are some individuals who inherit p53 mutations but that's a rare population. Most people have normal p53, but the tumor specifically generates mutations in p53. We have some new models that are going to more faithfully recapitulate that inactivation of p53 in a single cell." For Piwnica-Worms, also at MD Anderson, the path to the Institute of Medicine was illuminated by a glow familiar to most—firefly luciferase, the enzyme that causes fireflies to glow. As chair of the department of cancer systems imaging, Piwnica-Worms is focused on molecular imaging, which allows researchers to observe cancer cells at work in vivo, or inside the body. "What molecular imaging is about is trying to visualize molecular and biochemical events within the context of the body using external imaging devices," said Piwnica-Worms, a pio- neer in the development of the field. "Our particular area that we've empha- sized for many years involves using genetically encoded reporters—using the tools of cell and molecular biology to insert a reporter enzyme that, just the Roddenberry Stem Cell Center at Gladstone, is the nonresident scholar for biomedical research policy at Rice University's Baker Institute for Public Policy. A parameter for electing new mem- bers set by the Institute of Medicine is to build a diverse group of people from a variety of backgrounds, and these three new members embody that goal. They are all accomplished leaders in their respective fields, but each has arrived at this honor thanks to their own unique and groundbreaking body of work. For Lozano, the path to the Institute is connected to a different path: the p53 tumor suppressor pathway. For years, her work has been focused on the protein known as p53. When p53 is functioning properly, it prevents tumors from developing. B y S h e a C o n n e l l y S ince the 1970s, the beginning of fall is marked each year by a prestigious honor for up to 70 leaders in biomedical science, health care, health policy and related fields: election to the Institute of Medicine of the National Academies. Most years, members of Texas Medical Center institutions can be found among the new inductees, and this year is no exception. Three of the 70 new mem- bers announced in October have ties to the medical center. Guillermina Lozano, Ph.D., is chair of the department of genet- ics at The University of Texas MD Anderson Cancer Center, David Piwnica-Worms, M.D., Ph.D., is chair of the department of cancer systems imaging at MD Anderson, and Deepak Srivastava, M.D., the Younger Family Director of the Gladstone Institute of Cardiovascular Disease and director of

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