What is Cancer?

BY: LEEVI SYMISTER

Cancer is a general term that refers to a spectrum of over 100 types of diseases that arise in various parts of the body [1]. In general, all cancers include the uncontrolled formation of new damaged or abnormal cells within the body. We are made up of trillions of cells meaning that cancer can start and proliferate almost anywhere inside of the body [1]. This disease discriminates against neither age nor gender. Prostate Cancer is the most common type of cancer that occurs in men while in women Breast Cancer is most common. In children, however, the most common type of cancers are ones that relate to the blood, brain, and lymph nodes [2]. Cancer is the leading cause of death worldwide [9] and in 2021 alone an estimated 1.9 million people will have been diagnosed with cancer in the United States. Over six hundred thousand people are expected to die from cancer this same year [3]. 

So what exactly makes this disease so widespread and potent for many people every single year despite our seemingly advanced clinical technology and immune health? The answer lies in cancer's evasiveness to our immune system's defenses.

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Cells usually form through a process called Mitosis in which a cell divides producing two daughter cells of the same number and kind of chromosomes. When cells become old or damaged, they die and are replaced with new cells. Our body's cells run off of chemical signals that tell them when they should grow or divide and signals that tell them when they should die or stop dividing, a process known as Apoptosis. In cancer, however, this process can become hijacked where damaged and atypical cells grow without restriction. These cells then can accumulate and eventually form tissues called tumors [6]. What causes this behavior in cancerous cells are mutations (or alterations) of genes inside the DNA. The three main genes altered are Proto-oncogenes, Tumor Suppressor genes, and DNA Repair genes [1]. Proto-oncogenes are responsible for restricting cell growth. Mutated genes of this type are called Oncogenes and can allow cells to proliferate uncontrollably and resist the immune system [1]. Tumor Suppressor genes are responsible for preventing tumors. Mutations of this gene force it to become inactive allowing cells to divide uncontrollably [1]. DNA Repair genes can also be altered allowing mutations in the DNA to go unresolved leading to more damaged and abnormal cells. Mutations affecting these three types of genes can be in the form of rearrangements, duplications, and deletions [5] of sections of chromosomes that comprise our DNA. These mutations can even be inherited from an individual's parents if they are present in the gametes, or reproductive cells, that will later form the offspring [4]. With these changes cancer cells can spread and form tumors throughout the body in a process known as Metastasis [1]. 

Now that we understand what causes cancer inside of the body, let's look at the factors outside the body that can lead to cancer.

Cancer is caused by different carcinogens or substances capable of causing the mutations that develop cancer. It is these that alter the body's DNA and lead to tumors. Environmental carcinogens are things in the environment that can cause cancer. Ultraviolet rays from the sun, for example, can damage DNA and lead to certain skin cancers. Nuclear radiation is another environmental carcinogen that with prolonged exposure can lead to cancer development. DNA and RNA viruses that can hijack a cell's DNA and protein development mechanisms and subsequently duplicate themselves can also lead to cancers [6]. Notably DNA viruses such as the Epstein-Barr, Human Papilloma, Hepatitis B, and Human Herpesvirus-8 and RNA viruses such as Human T Lymphotropic Virus Type 1 and Hepatitis C [7] contribute to cancer rates. Carcinogens can also be things such as one's diet and smoking habits [6].
Potential treatments for cancer include Biomarker testing, Hormone therapy, Immunotherapy, Chemotherapy, Radiation therapy, Stem Cell transplant, Surgery, or Targeted Therapy. Most people will have a combination of these treatments [8] in order to either ease their cancer symptoms or eliminate cancer from their body entirely. What treatment(s) a person will need depends upon the type of cancer they have and how much it has progressed [8]. Each treatment comes with its own risks and side effects which the patient will have to evaluate before receiving their treatment. 

Cancer is a deadly disease that claims the lives of millions of people worldwide every single year. Despite this discouraging figure, it is important that people remain vigilant in preventing cancer from entering their lives in any way that they can. This can be through a change in one's diet, quitting smoking, and avoiding exposure to environmental carcinogens to the best of one's ability. With this and the continued research and advancement of science and technology, we can hope to one day live in a world where cancer is not a dominant occurrence in our everyday lives. ​

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Works Cited

"What Is Cancer?" National Cancer Institute. Web.

Hassanpour, Seyed Hossein, and Mohammadamin Dehghani. "Review of Cancer from Perspective of Molecular." Journal of Cancer Research and Practice. No Longer Published by Elsevier, 10 July 2017. Web.

"Common Cancer Sites - Cancer Stat Facts." SEER. Web.

"The Genetics of Cancer." National Cancer Institute. Web.

Lobo, I. (2008) Chromosome abnormalities and cancer cytogenetics. Nature Education 1(1):68 
Trichopoulos, Dimitrios, et al. “What Causes Cancer?” Scientific American, vol. 275, no. 3, 1996, pp. 80–87. JSTOR, www.jstor.org/stable/24993351. Accessed 12 Sept. 2021. 
Liao, John B. “Viruses and human cancer.” The Yale journal of biology and medicine vol. 79,3-4 (2006): 115-22. 

"Types of Cancer Treatment." National Cancer Institute. Web.
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"Cancer." World Health Organization. World Health Organization. Web.