Breast Cancer Diagnosis And Testing Essay.

Benign vs Malignant tumors

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.

A tumor is not necessarily cancerous or malignant, as it has the probability of being benign. At the cellular level, malignant tumor cells are irregular in shape, proliferates faster and have a tendency to spread to different body parts (Patel 2020), while the benign tumor cells have smooth, distinct and regular shape, proliferates at a slower pace and do not invade other organs. 

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.

According to Eldridge (2022), generally, cells spend more time at interphase, in which they develop and grow to a size that is double of its initial and prepare themselves for cell division. Hence, according to the above data, the cells can be considered as cancerous as most of them are at interphase, preparing themselves for division.

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?

Cell receptors are made up of macromolecules like carbohydrates and proteins (Chen et al. 2017). Its monomers are monosaccharides and amino acids respectively (Alen 2018).

1. What is the role of cell receptors in cellular function?

Cell receptors are those transmembrane macromolecules which remain present either inside or on the surface of the cell. Its main function is to receive chemical signals released by itself or any other cells and activate cell function. It helps in transmembrane signal transduction and changes the cell activity (Xu, Li & Xu, 2020). 

1. 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.

Estrogen plays an important role in the detection of breast cancer. Jameera Begam, Jubie & Nanjan (2017) observed the involvement of estrogen receptors in breast cancer. In the cancerous cells, when the hormone attaches to the receptors, the cancerous cell proliferates and accelerates its growth. 

Pathologist Cell Receptors and Testing

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.

3. 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.

Genes are a part of the deoxyribonucleic acid (DNA) chain which are composed of double-chained nucleotides in a specific sequence. Genes are essential for every living organism to survive as these contain the necessary information encoded within itself. Its function is determined by the DNA sequence of which it is a part of. 

1. 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?

A mutation can be defined as any change in the nucleotide sequence of DNA of a cell. This wrongly coded sequence translates into faulty proteins which are either dysfunctional or cause harm to the cell.

All mutations are not harmful, as some can bring about positive changes within the organism.

Silent mutation does not lead to a change in protein structure. 

1. 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.

DNA replication occurs in 4 steps-

1. Formation of replication fork- The DNA strands separate from each other.
2. Binding of primer- The primer binds to the DNA sequence to initiate replication.
3. Elongation- New strand is created by the action of DNA polymerases.
4. Termination- Removal of the primer by exonucleases and DNA ligase joins the strands together. 

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.

The molecular genetics of the central dogma states that the DNA of a cell is transcribed into an mRNA which is then translated into a protein. In the process of replication, the DNA is replicated into a small strand of mRNA. The mRNA in turn directs the ribosomes to form specific proteins. In this way, the flow of information takes place. 

1. 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.

All cells have the same amount of DNA present within them. But different parts of the DNA get transcribed to form proteins in different cells to perform their specific functions. Differential gene expression in cancerous cells make them immortal while the general characteristics of the non-cancerous cells is mortality. 

1. This Oncotype test uses microarray analysis to determine gene expression. Explain to Ann what a microarray is.

A microarray is a tool which is used to collect several microscopic DNA and detect the gene expressions of these DNA. These extracted DNA or genes are arranged in the pattern of a grid and is used to determine the genotype of multiple regions of the genome. 

1. 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?)

BRCA1 is a tumor suppressor gene which makes proteins that prevents the formation of tumor by preventing uncontrolled and rapid cell division. It helps to repair any damage caused to the DNA. Thus, a decrease of BRCA1 protein can lead to an increase in rapid cell division, a property of cancerous cells. 

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?

Mutation, BRCA1 and BRCA2

Chemotherapy is the method of using appropriate drugs to prevent the cancer cells from growing and dividing as they divide rapidly and uncontrollably (Amjad, Chidharla & Kasi, 2021). 

1. What are some side effects of chemotherapy?

Some side effects of chemotherapy are-

1. Tiredness or fatigue;
2. Nausea;
3. Vomiting;
4. Loss of appetite;
5. Diarrhea;
6. Hair loss. 

1. Based on your knowledge of chemotherapy and cell division, why do you think chemotherapy leads to these side effects?

Chemotherapy is intended to prevent the fast-growing cells from proliferating. Hence, it is effective in case of cancer cells. But in the course of this process, it kills the healthy cells which are fast-growing. This leads to the expression if side effects. 

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?

Taxol targets microtubules (Yang & Horwitz, 2017).

2. What are the functions of this structure in the cell?

Microtubules are those cell structures which provide a specific shape to the cells and during cell division, help in the formation of spindle fibers. 

3. How does the targeting of this structure treat cancer?

As microtubules are involved in cell division, hence, if they are targeted, then, the process of rapid cell division can be prevented. It can trigger cell apoptosis leading to its death. 

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?

The presence of cancer cells in the lymph nodes acts as an indicator of the spread of cancer. If cancer cells are not detected in the lymph far away from the region of tumor, then, it is a good sign as it would denote that cancer cells have not spread to far off regions (Farnsworth, Achen & Stacker, 2018). 

2. What does metastaticmean in cancer diagnosis? Based on the above information, had Ann’s cancer metastasized? Support your answer.

Metastasis is the process of movement of cancer cells from one part of the body to another. This occurs when the tumor is invasive in nature (Farnsworth, Achen & Stacker, 2018). Ann’s cancer is not metastasized as the tests reported that the cancerous cells were not found in any distant parts of the body away from tumor.

References 

Amjad, M. T., Chidharla, A., & Kasi, A. (2021). Cancer Chemotherapy. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK564367/ 

Begam, A. J., Jubie, S., & Nanjan, M. J. (2017). Estrogen receptor agonists/antagonists in breast cancer therapy: A critical review. Bioorganic chemistry, 71, 257-274. DOI: 10.1016/j.bioorg.2017.02.011

Chen, J., Than, A., Li, N., Ananthanarayanan, A., Zheng, X., Xi, F., ... & Chen, P. (2017). Sweet graphene quantum dots for imaging carbohydrate receptors in live cells. FlatChem, 5, 25-32. https://doi.org/10.1016/j.flatc.2017.08.006

Eldridge, L. (2022). CANCER: A DISEASE OF THE CELL CYCLE [Ebook]. The American Cancer Society. Retrieved 19 April 2022, from https://www.prospectridgeacademy.org/ourpages/auto/2017/10/23/56908753/Day%2010%20-%20Article%20-%20Cancer%20Basics%20_revised_.pdf.

Farnsworth, R. H., Achen, M. G., & Stacker, S. A. (2018). The evolving role of lymphatics in cancer metastasis. Current opinion in immunology, 53, 64-73. https://doi.org/10.1016/j.coi.2018.04.008

Patel, A. (2020). Benign vs malignant tumors. JAMA oncology, 6(9), 1488-1488. doi: 10.1001/jamaoncol.2020.2592

Xu, X., Li, H., & Xu, C. (2020). Structural understanding of T cell receptor triggering. Cellular & Molecular Immunology, 17(3), 193-202. https://www.nature.com/articles/s41423-020-0367-1 

Yang, C. P. H., & Horwitz, S. B. (2017). Taxol®: the first microtubule stabilizing agent. International journal of molecular sciences, 18(8), 1733. https://doi.org/10.3390/ijms18081733