Addresses course outcomes 1 and 4:
- use knowledge of biological principles and the scientific method to ask and answer relevant questions about the human body
- weigh and make health-related decisions based on an understanding of the value and limits of scientific knowledge and the scientific method
Before attempting this assignment, you might want to revisit the Scientific Method Tutorial in the Science Learning Center under the Course Content area.
Substance in Green Tea Inhibits Inflammatory Breast Cancer Cells
Inflammatory breast cancer (IBC) is a rare and often fatal form of breast cancer. In IBC, lymphatic vessels in the skin are blocked causing the breasts to appear swollen and red. Early in the disease process, patients with IBC usually do not have the classic “lump” in their breast; therefore the disease is frequently diagnosed at later stages. Diagnosis is often so delayed that the cancer has metastasized and patient prognosis is poor.
The underlying cause of IBC is unknown, but it is believed that like with other cancers cetain cell types have the abililty to transform into cells that can form malignant tumors. These aberrant cells are considered cancer stem cells, and populations of cancer stem cells have been identified in IBC.
In a recent, study researchers evaluated whether a metabolite found in green tea could inhibit the growth of certain stem cell types that have been identified in the breast tissue of patients with IBC. In this study, two IBC stem cell types, SUM-149 and SUM-190, were exposed epigallocatechin-3-gallate (EGCG- is a potent antioxidant found in green tea). Results from the study showed that EGCG treatment inhibited the growth, spread, and survival of the two stem cell types.
For the following questions, please refer to the original paper. The link to the paper is: http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0073464&representation=PDF
- What is the overall hypothesis of this experiment? (Reminder: a hypothesis is a statement that can be tested).
- In the Materials and Methods section of the paper, the authors discuss the cell culture and treatment conditions. What was the control group treated with in this section (make sure to look only at the Cell Culture and Treatment section of the paper)? Why?
- Again, looking only at the Cell Cuture and Treatment section, what was the experimental group treated with? Why?
- In the Results section of the paper, the authors summarizes their multiple findings. In the “EGCG Reduces Growth of Pre-existing Tumors Derived from SUM-149 Stem-like Cells” results sub-section, the authors report many specific findings. What is one of those specific result reported?
- Did the researchers follow the scientific method in their experimental design? Explain.
- Based on the results, was the hypothesis supported, and what can you conclude from this experiment?
Mineva et al. (2013). Epigallocatechin-3-gallate inhibits stem-like inflammatory breast cancer cells. PLoS ONE, 8(9): e73464. Doi:10.1371/journal.pone.0073464