Topic Abstract: The Tumor Microenvironment

Dietmar W. Siemann, Ph.D.

Professor & Associate Chair for Research, Department of Radiation Oncology

Associate Director, Education & Training, UF Health Cancer Center

Presentation Title: The Tumor Microenvironment

For tumors to grow beyond a size of a few millimeters, they must induce new blood vessels to meet the nutritional needs of the cancer cells. Because cancer cell populations continue to expand, the supporting tumor blood vessels do not mature and therefore remain structurally and functionally abnormal. As a consequence, the cellular microenvironments of tumors are unlike any found in normal tissues. The physical conditions that arise are imposing and include elevated interstitial pressure, localized extracellular acidity, and regions of oxygen and nutrient deprivation. No less important are the functional consequences experienced by the tumor cells residing in such environments: adaptation to oxygen deprivation, cell quiescence, modulation of transporters and critical signaling molecules, immune escape, and enhanced potential to spread (metastasis). Together, these factors lead to therapeutic barriers that create a significant hindrance to the control of cancers by anticancer therapies including radiation, chemotherapy, and immunotherapy. However, the abnormal nature of the tumor microenvironments that distinguish tumors from normal tissues also offers unique therapeutic opportunities. Indeed, emerging research suggests that interventions that seek to improve tumor physiology or approaches that selectively target key elements of the tumor microenvironment may lead to improvements in cancer treatment outcomes.

Dr. Siemann is a cancer biologist at the UF Health Cancer Center. His research focuses on experimental approaches to develop novel anticancer therapies that will enable the development of future clinical treatment regimens designed to improve cancer prognosis and survival.

Core Standards

SC.912.L.14.34 Describe the composition and physiology of blood, including that of the plasma and the formed elements.

SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both individual and public health.

SC.912.L.16.8 Explain the relationship between mutation, cell cycle, and uncontrolled cell growth potentially resulting in cancer.

SC.912.P.8.10 Describe oxidation-reduction reactions in living and non-living systems.

SC.912.L.14.2 Relate structure to function for the components of plant and animal cells. Explain the role of cell membranes as a highly selective barrier (passive and active transport)

SC.912.L.14.52 Explain the basic functions of the human immune system, including specific and nonspecific immune response, vaccines, and antibiotics.

SC.912.L.14.In.c Identify that parts of cells (organelles) can combine to work together.

SC.912.L.14.In.d Describe common human health issues.

SC.912.L.18.6 Discuss the role of anaerobic respiration in living things and in human society.

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