Typically, a middle school life science study of cells explores the parts of the cells, cell diversity and how cells reproduce through mitosis. Discussion of cancer at this time is appropriate since cancer cells share the needs of normal cells in terms of obtaining nutrients and getting rid of waste. However, they differ in their cell cycle. Cancer cells lack an interphase–meaning they are in a near constant state of reproducing with little down time in-between divisions. This leads to the formation of a mass of undifferentiated cells, a tumor.

Angiogenesis is the tumor’s ability to construct blood vessels that become the circulatory system for the tumor. Thus, needed oxygen and nutrients are effectively delivered and waste is removed, allowing the tumor to thrive. These blood vessels are also potential blood-letting points, increasing the risks of surgical removal. If angiogenesis is curtailed, the tumor is deprived and fails to thrive reducing potential surgical complications.

On April 19, 2008, ScienceDaily reported that a team of researchers in Australia has identified a master gene responsible for angiogenesis. The gene is named RGS5. The team was able to remove the gene from experimental tumor cells, and this caused angiogenesis to reverse itself! This means that oncologists may have another tool to treat cancers in more targeted ways; ways that do not affect healthy cells, only cancerous cells.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Ask students what cells need to thrive. Their list should be consistent with what all living things need: ability to take in nutrients and get rid of waste, to manufacture needed materials and break down no longer needed materials, and to reproduce. It might be appropriate at this time to show them a schematic of the cell cycle. What are student conceptions of cancer and tumors? Ask if they think cancer cells have different needs than those already discussed? Why or why not?

What is a tumor? How might it differ from or be the same as other organs in the body? A tumor is a mass of undifferentiated cells as opposed to cooperative tissues organized in a functional organ. And it is not part of a functional organ system except in the sense that the tumor’s blood vessels are derived from the healthy organ system’s blood vessels: cells come from other cells.

Lead students to conclude that cancer cells are like other cells with respect to the cell cycle and needs. Then ask, so how is it that cancer cells can grow into a tumor while healthy cells do not? Lead students to the one difference in the cancer cell cycle as compared to healthy cells’ cycle: lack of interphase. The lack of interphase may be attributed to a genetic mutation that fails to produce the needed proteins that signal interphase, or an environmental factor that prevents detection of the interphase signal.

At this point, you have raised student awareness of the nature of cancer cells and tumors. The students are now ready to hypothesize ways to interfere with tumor growth. Solicit and accept all reasonable hypotheses. Ask what if there was a way to control/eliminate a tumor’s ability to construct blood vessels? What do you predict the outcomes might be? Why? What leads you to believe that is a reasonable prediction? Make sure students use known facts about cell structure and function to support their predictions.

Have students read the article: World-first Discovery Could Help Treat Life-threatening Tumors. What other questions come to mind, questions which there are no pat answers to at this time? For example, does RGS5 also control blood vessel formation in healthy tissue and organs? How can it be controlled to impact only tumor blood vessels? What other investigations are needed in order to learn how to use this science knowledge, to apply it to a technological innovation to treat cancer?

The lesson described connects to both the Life Science and the Science as Inquiry content standards of the National Science Education Standards. Here are some additional resources from the National Science Digital Library Middle School Portal related to gene function, cells, and cancer: The Genetic Science Learning Center: The Basics and Beyond; Cell Differentiation; Lessons on Cells, Tissues ,and Organs; and Science sampler: Cancer-Mitosis Run Amok.

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