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PRECISION-GUIDED TUMOR KILLERS

Elvia Anguiano

Moraine Valley College

Elvia’s informative speech focuses on an experimental cancer treatment that may improve on current chemotherapy techniques. She uses a categorical (topical) pattern to explore the current methods and to describe the benefits, pitfalls, and possibilities for this new treatment. By praising the possible benefits of the technique while also exploring some potential drawbacks, Elvia informs her audience ethically by showing different sides of the topic.

Have you ever heard one of those parodies of medicine ads before? You know, one that goes something like: “If you suffer from back pain, then BelieveAll is the right medication for you. Before taking BelieveAll, ask your doctor. Some side effects include insomnia, kidney infections, heart attacks, infertility for men and women under thirty-five, uncontrollable flatulence, and spontaneous self-combustion.” •

• Humorous attention-getter will connect with many audience members.

Parodies like these can be very funny, but real side effects are not. As many cancer patients will probably tell you, one of the scariest things about having cancer is the treatments themselves—because of their horrible side effects.

But it may no longer have to be this way. Today I’m here to tell you about an experimental new method of chemotherapy—precision-guided tumor killers, or PGTKs • —and the possibility of its eradicating tumors more effectively than traditional chemotherapy, without all the horrible side effects. •

• By using the acronym “PGTK,” Elvia creates a memorable label. Since the label itself is a kind of jargon, she makes sure to explain this acronym a second time, later in the speech.

• Elvia offers a precise statement of her topic.

So that you may all get an idea of the importance of this new method, keep the following estimates in mind: the National Cancer Institute’s Web site, accessed September 30, 2006, estimated that in 2006 there would be more than 1.3 million new cases of cancer and over 500,000 deaths in the U.S. alone. Furthermore, an article in the March 23, 2007, Chicago Tribune noted that, as of right now, one in twenty people worldwide has cancer. By 2020, that number will be one in nineteen. Think of the hundreds of people you have seen today, all the people here that could now have cancer or one day have cancer. •

• Elvia offers statistics about cancer rates to show relevance to listeners.

So that you may all better understand PGTKs, you need to learn a little bit more about traditional chemotherapy, what PGTKs are, how they work, and finally their future potential and current limitations. •

• Elvia offers a preview of main points.

Today, chemotherapy is one of the most commonly used methods to fight cancer. To understand why its use has become so widespread, we need to learn what it is, how it works, and why it has such horrible side effects. To begin with, chemotherapy was first developed in the 1950s—as reported by the Web site of the American Cancer Society, accessed November 27, 2006—when some people were accidentally exposed to mustard gas in a government weaponry experiment and the exposure resulted in a lowered white cell count. This intrigued the scientists, who then injected mustard gas into cancer patients and were shocked at the remarkable improvements. This discovery led to the development of many other drugs that now treat cancer. Today, chemotherapy is a mixture of many of those drugs.

Now that we know what chemotherapy is, we will move on to how it works. • According to the American Cancer Society Web site, accessed September 30, 2006, chemotherapy may be administered into the body through three different methods: a pill, a shot, and an IV. The chemotherapy then courses through the body, seeking any cells in the process of reproduction. It then poisons those cells so that when they try to reproduce, or split, they are unable to and therefore die off.

• Elvia offers a quick internal preview.

Although chemotherapy has been very effectively attacking cancer for the past sixty years, there is one major drawback: chemotherapy cannot tell the difference between actively reproducing cells of cancer and those of normal tissue. This is why so many chemotherapy recipients suffer such horrible side effects, including fatigue, nausea and vomiting, pain, hair loss, blood clotting problems, and effects on vital organs. •

• An effective explanation of the chemotherapy process and its drawbacks.

Now that we know a little bit more about traditional chemotherapy, we may move on to the new method: precision-guided tumor killers, or what I referred to earlier as PGTKs. These are hollow spheres that are one thousand times smaller than the size of a pinpoint. PGTKs are filled with small doses of chemotherapy and are studded with aptamers on the outside. According to Dr. Omid Farokhzad, aptamer researcher and assistant professor at Harvard Medical School, quoted in the August 2006 issue of Popular Science, “aptamers are like the GPS in your car. They allow the direct delivery of the PGTKs to cancer cells, leaving all normal cells in the body alone.” •

• Analogy helps clarify a potentially complex idea—aptamers are like a car’s GPS.

PGTKs are designed to work in a very similar way to chemotherapy. The PGTKs are injected into the body. They then course through the blood searching for any cancer cell, using their GPS system. Once they find a cancer cell, they latch onto that cancer cell in a similar way to standard chemotherapy. After a while, the cancer cells absorb the PGTKs. Inside, the PGTKs open up and release the chemotherapy. Once poisoned, the cancer cells burst and die off. •

• Explanation of the PGTKs’ process highlights advantages as compared to the earlier explanation of traditional chemotherapy.

Having learned what the PGTKs are and how they are designed to work, we may now focus on why they may prove more effective and better tolerated than traditional chemotherapy. According to the April 10, 2006, issue of the Proceedings of the National Academy of Sciences, researchers compared these chemo-loaded nanoparticles to regular chemotherapy in mice with prostate cancer. They found that after a single injection of the PGTKs, complete tumor reduction was observed in five of seven mice with a survivability of 100 percent. In contrast, two of seven mice in the chemotherapy group had complete tumor reduction with survivability of only 57 percent.

Thus far, Dr. Farokhzad’s research has been most effective in targeting prostate cancer cells. As he noted in an interview published in the November 10, 2005, issue of Nano World News, “we wanted to focus on a cancer model where a localized tumor has a localized way of being treated in clinical practice.” And Dr. Farokhzad’s research has been well received in the medical and scientific communities; in the last several years he and his colleagues have published numerous articles in leading peer-reviewed medical journals, including the July 2006 issue of the American Journal of Drug Delivery, the February 2007 issue of Biomaterials, and the October 2007 issue of Nanomedicine. •

• Citing several peer-reviewed sources helps support Elvia’s credibility.

Expressing his high hopes for the future of PGTK therapy, Dr. Farokhzad noted in Science Central News on May 11, 2006, that “our system is both significantly more effective than traditional chemotherapy and remarkably less toxic, allowing the long list of chemotherapy side effects to shorten significantly, and allowing cancer patients to continue with their current lifestyles.” Venture capitalists seem to agree. The November 27, 2007, issue of Red Herring, a business and technology magazine, reported that a biotechnology company called Bind-Biosciences, cofounded by Dr. Farokhzad, had raised approximately 16 million dollars in a second round of venture capital funding—all for the purpose of developing these nanoparticles further. The same article added that demand in the United States for nanotechnology-based medicines could grow to 39 billion dollars by 2011 and up to 82 billion dollars by 2016.

Having learned about PGTKs, it is time to look into the future potential and current limitations of this new system. Although the future uses for the PGTKs are focused mainly on treating cancer, they are not limited to it. Since the PGTKs really are hollow spheres, the medicine inside can vary. Also, researchers are working toward a system whereby the aptamers’ target can be changed—just like the target on your GPS—expanding the use of the PGTKs to other diseases and procedures. For example, if you fill the PGTKs with small doses of Carbatrol and target the aptamers to nerve cells in the brain, you could treat epilepsy. Or, as reported on the National Cancer Institute’s Web site, accessed October 1, 2006, if you fill the PGTKs with mercury and target a specific organ in the body, you could make CT scans and other imaging procedures much more accurate and the diagnoses of doctors much more accurate.

Although the promise of PGTKs is extraordinary, there are some drawbacks. • As Professor Miqin Zhang—a material scientist at the University of Washington in Seattle—stated, one drawback is that the PGTKs must remain separate to do their job. If they should join together, they become toxic to healthy tissue. Another drawback that Professor Zhang mentions is that at different stages of development, cancer cells have different molecular makeup. So, the PGTKs could easily detect an early stage of cancer using their GPS system, but they may not be so successful at a later stage of cancer. Keeping these drawbacks in mind, scientists continue to do research and testing to confirm their findings.

• Elvia acts as an ethical informative speaker by noting drawbacks of PGTKs.

Looking back, we’ve learned a little bit more about traditional chemotherapy. We’ve learned about a new system known as PGTKs, their future potential, and current limitations. • Cancer patients suffer enough with the pain and fear of having cancer. They should not have to increase their pain and suffering because of treatments that are supposed to save their lives. Perhaps one day you or someone you know may have cancer, and in fact, you probably will know someone who does. Just remember that neither you nor they may have to suffer or die; should this treatment be perfected and approved, patients will gladly take it. The ads for these new medicines would not need to be parodied as yet another treatment with horrible side effects. Instead, this could be a case in which the medicine is actually better than the side effects. •

• “Looking back . . .” indicates the start of the conclusion, followed by a summary of main points.

• Clincher is a compelling hypothetical example that reconnects with the introduction.