Technologies for Understanding and Treating Cancer

JULIE CHAMPION
Georgia Institute of Technology

PETER TESSIER
Rensselaer Polytechnic Institute

Cancer is a complex group of more than 100 diseases characterized by uncontrolled cell growth. Approximately 40 percent of people will be diagnosed with a form of cancer in their lifetime, and about 15 percent of all people will die from cancer. This has motivated a significant amount of research to better understand and treat these devastating diseases.

At the molecular level, cancer is caused by mutations in genes that regulate several important cellular functions. These genetic mutations may be inherited, acquired via exposure to environmental hazards (e.g., chemicals in tobacco smoke, radiation, sunlight), or caused by unknown factors.

Human cells normally grow and divide as needed and die when they are old, damaged, or overcrowded. Cancerous cells fail to respond to normal signals that regulate cell growth and death, leading to uncontrolled growth. In some cases such growth leads to the formation of large cellular masses (tumors), in others it does not (as in cancers of the blood). Malignant tumors can spread into nearby tissues, and cancerous cells can break off tumors and travel to other parts of the body to initiate the formation of new tumors.

The ability of cancer cells to coopt normal cells to form blood vessels to feed tumors and remove their waste is critical to sustaining their uncontrolled growth. Another key is their ability to evade the immune system that normally eliminates damaged or abnormal cells from the body.

Cancer presents a number of challenges that engineers from different disciplines are working to address. Understanding how cancer develops and what makes some cancer cells migrate to new sites is essential to identify the necessary conditions for these events and how they may be prevented or arrested. Early detection of cancer is known to be an important factor in survival, but more sensi-

tive and selective tools are needed to identify rare cancer cells and biomolecules indicative of cancer from highly complex biological mixtures such as blood.

Treatment of cancer also has many challenges, including high toxicity in healthy tissues, development of drug resistance, and the need to better match drugs with particular cancer subtypes. New methods of drug delivery to specifically target cancer cells and alternative therapeutic approaches with new molecules and/or physical ablation methods are needed. Additionally, better imaging methods are necessary to identify smaller tumors, assist surgeons in completely and specifically removing cancerous cells, and track response to treatment. These challenges require biological and molecular expertise together with engineering innovation.

The first speaker, Cynthia Reinhart-King (Cornell University), set the stage by discussing how cancer cells go awry. She explained how extracellular signals and the microenvironment around cancer cells influence their uncontrolled growth and expansion.

Brian Kirby (Cornell University) then addressed cancer detection. He reviewed recent advances in detecting rare cancer cells using microfluidics that can be used for noninvasive detection and improved diagnosis and treatment planning.¹

Next, Jennifer Cochran (Stanford University) described methods for interfering with the spread of cancer—specifically, therapeutic molecules that block the ability of cancer cells to leave the initial tumor and start new ones.

Finally, Darrell Irvine (MIT) discussed strategies for harnessing the immune system to target and destroy cancer cells. He highlighted approaches that use materials science and biotechnology methods to control and sustain antitumor immune responses specific for different types of cancer.

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¹ Paper not included in this volume.