Question

The Case Study in Cancer

Part I

Ann is a 27-year-old nurse working at the local hospital in surgery. She had worked hard to move into the specialty, and she was enjoying her career, friends, and family. She and her partner had been living together for about a year, and she was content. As a nurse, Ann knew the importance of doing breast self-exams, and did them regularly. In the shower one morning, she felt a lump she wasn’t familiar with. Ann was a bit worried, even though there was no history of breast cancer in her family, so she made an appointment with her doctor.

1. If Ann has a tumor in her breast, is it necessarily cancerous? Differentiate between a benign tumor and cancer at the cellular level.
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Part II

Ann’s doctor is worried enough to send her to a breast cancer specialist, just to be safe. Ann makes an appointment and is referred for a mammogram, which will image the soft tissue in the breast. After the mammogram and an exam, she meets with the surgeon, Dr. Hernandez. Dr. Hernandez is also concerned, as she felt and has images from the mammogram of a small tumor. She recommends a biopsy of the tumor as soon as possible. Ann goes in the same day for the quick surgical procedure where a needle is inserted and part of the tumor is taken for analysis. The tumor will be analyzed by a pathologist, a specialist in looking for disease in tissue samples.

1. The pathologist examines the cells taken from the tumor, particularly the number of cells in mitosis. Below are the results. In normal breast cells, one would expect 0-4 cells per 10 high-powered field of view (microscopy) undergoing mitosis.

Based on the above results, what can you conclude about the tumor cells? Can you say definitively that they are cancerous? Be sure to support your answer with the data above.
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2. The pathologist also looks for three receptors on the tumor cells: estrogen receptors, progesterone receptors, and HER2 receptors.

1. What type of macromolecule class are cell receptors? What is the monomer?
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2. What is the role of cell receptors in cellular function?
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3. Ann’s tumor was positive for estrogen and progesterone receptors, but negative for the HER2 receptor. What is the role of estrogen receptors on a cell? Remember to cite your sources using APA Style.
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Part III

Dr. Hernandez sits down with Ann and her partner. The doctor is sorry to report that Ann has breast cancer; however, because it was caught early and responds to estrogen and progesterone, the prognosis is good. At this point it looks like the cancer is stage 1. However, as Ann is young, the doctor wants to perform a couple tests. The first test is a genetic sequencing test for BRCA1 and BRCA2, as well as testing for other genes known to increase the risk of cancer. The other test is an Oncotype DX test on the tumor cells. This is a gene expression test, where the results correlate with how aggressive the cancer cells are. Ann is overwhelmed, but wants to do everything she can to get rid of this disease.

1. As a result of your discussions, you know that mutations in BRCA1 and BRCA2 increase the risk of breast cancer. Because of this, a positive test for these mutations would mean different treatment for Ann, including removal of both her breasts (bilateral mastectomy) as well as her ovaries to prevent ovarian cancer. Ann decides to have the test done, but she is a little hazy on the biology of DNA.

1. Describe the basic structure and function of a gene.
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2. At the molecular level, what is a mutation? Are all mutations harmful? What type of mutation does not lead to a change in protein structure?
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3. The polymerase chain reaction (PCR) is a method that can be used to detect mutations. It uses machinery similar to your cells to replicate a specific DNA sequence, which in this case would be only the mutated gene. Describe the basic process of DNA replication in a cell.
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2. Also, as a result of your discussion, you know that the expression of genes can change in cancerous cells versus noncancerous cells. The Oncotype test will look at the expression levels of several genes in her tumor cells by looking at the mRNA produced.

1. What role does mRNA play in the flow of information in the cell? (Hint: Remember the central dogma of molecular biology.) Please include the basic flow of information in the cell.
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2. Cancer cells and noncancerous cells may have almost identical DNA; however, gene expression can change. Explain the concept of differential gene expression using cancer versus noncancerous cells as an example.
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3. This Oncotype test uses microarray analysis to determine gene expression. Explain to Ann what a microarray is.
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4. The results of Ann’s Oncotype test showed a decrease in the expression of BRCA1. How can this decrease lead to an increase in cell division? (Hint: What is the normal role of BRCA1?)
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3. Both these tests take time and will inform Ann’s treatment plan for the best possible outcome. While she is waiting on results, Ann begins to research the main types of treatments that are available to treat breast (and many other) cancers. One of these is chemotherapy. There are many types of chemotherapy, but in general:

1. How does chemotherapy work?
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2. What are some side effects of chemotherapy?
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3. Based on your knowledge of chemotherapy and cell division, why do you think chemotherapy leads to these side effects?
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Part IV

Dr. Hernandez calls Ann with the test results a couple weeks later. She is negative for the BRCA1 and BRCA2 mutations, which is good news. But her Oncotype score is borderline high, meaning the cancer is somewhat aggressive, and chemotherapy will decrease the chance that cancer recurs elsewhere in her body and increase her chances of survival long term. The surgeon recommends a medical oncologist to start chemotherapy, who in turn recommends a course of chemotherapy that includes paclitaxel, also known as Taxol.

1. What cell structure does Taxol target?
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2. What are the functions of this structure in the cell?
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3. How does the targeting of this structure treat cancer?
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Part V

After four rounds of chemotherapy and a unilateral mastectomy, Ann was exhausted but relieved to be through the worst of treatment. Radiation was not necessary, and the cancerous cells had not spread to any of her lymph nodes. These were all good signs that the cancer was caught early and had not spread. Ann was back to work, and aside from some fatigue, things were slowly getting back to normal (or as normal as they ever would be again). Ann and her partner were to be married in a year. They figured if they could get through this, they could get through anything together. Ann was excited to get on with planning the rest of her life!

1. Why is it a good sign that cancerous cells had not spread to her lymph nodes?
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2. What does metastatic mean in cancer diagnosis? Based on the above information, had Ann’s cancer metastasized? Support your answer.
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Answer 1

Part I

1. No, it is not necessary that if Ann have tumor in her breast, it is not necessary that she can cancer. This is because tumor could be of two types. Benign tumor is not malignant that is only develop cancer. Benign tumor cells have no ability to move from one place of the body to another.

Part II

. She has not cancerous cells because tumor cells are not showing high rate of mitosis. Because normal breast cell have high rate of mitosis as compared to the tumor cell.

a. The receptor is an protein macromolecule.

b. Function of cell receptor is to receive the information that they got from extracellular environment and pass this information to the inside the cell.

c. Estrogen receptors are involved in receiving the signals that are required for the growth and development of breast cell.