Cancer: A Brief Overview

Chavy Dworkind
Mar 13, 2021
5 min read

Chavy Dworkind

Published Saturday, March 13, 2021

Cancer is a complicated disease and my goal in this blog is to highlight the primary aspects of the disease in a way that is straightforward and relatively brief.

Cancer is a term that refers to many diseases because it can occur in any part of the body and there are groups of cancers with unique sets of characteristics. However, all cancers develop as a result of the same fundamental process. That is - when normal cell division goes awry and becomes abnormal and detrimental to the body (Understanding).

Image by OnHealth via https://www.onhealth.com/content/1/cancer_types_treatments.

Terms

Tumour: A tumour is a mass of tissue that results from cells which divide too much or from cells which do not die when they should (Tumour).
Malignant tumour: Malignant tumour cells can spread to nearby cells and to far away cells by travelling through the circulatory or lymphatic systems (What).
Benign tumour: Benign tumours do not spread or affect other cells in the body. They can sometimes be removed by a doctor and they do not usually grow back. An exception is that benign tumours in the brain can be fatal (What).
Metastasis: Metastasis occurs when cancer cells depart from their initial location and travel through body to another location where they form more tumours. The new tumours formed are the same kind as the initial tumour (What).

What is Mitosis?

Let’s start with the basics and review normal cell splitting in the body, called mitosis. Mitosis is a normal process that occurs in healthy cells. The process begins with cell growth, followed by DNA replication and lastly, the cell splits into two cells which are genetically identical to their mother cell. Mitosis occurs when defective or old cells need to be replaced by new cells.

Mitosis is viewed as a four phase process. The four phases are as follows:

Prophase: The genome becomes visible as chromosomes.
Metaphase: The chromosomes aline at the center of the cell.
Anaphase: The centromeres of sister chromatids are pulled apart.
Telophase: *Cytokinesis and the formation of a nuclear membrane.

*Cytokinesis is the physical process of the splitting of the cell (Chit).

There is a lot more to say on the topic of mitosis but we will keep it short and focus on cancer. There is a link at the bottom for further reading on mitosis. The image below portrays a simple representation of mitosis.

Image by BioNinja via https://ib.bioninja.com.au/standard-level/topic-1-cell-biology/16-cell-division/mitosis.html.

What is cancer?

Cancer essentially refers to cells in the body that split more than they should or cells that don’t die when they should. The cancer cells divide uncontrollably and the new cancer cells also divide uncontrollably. Sometimes, cancer cells form tumours. On the other hand, there is a form of cancer called leukemia, which exists in the blood and those cancers usually do not form tumours (What). Additionally, Leukemia originates in bone marrow. The bone marrow cells experience a leukemic change which can enable them to grow and divide. The leukemia cells can thrive while stifling the normal cells. Eventually, the normal cells do not grow and develop as they should because of the growing and dividing population of leukemia cells. There are many types of leukemia. For example, acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia, and hairy cell leukemia, to name a few (Leukemia).

Types of Cancer

Carcinoma: A cancer that originates in the skin or in the tissues that line other organs.
Sarcoma: A cancer that originates in the connective tissues of bones, muscles, cartilage, and blood vessels.
Leukemia: A cancer that originates in the bone marrow.
Lymphoma and myeloma: Cancers of the immune system (What Do).

More specific types of cancer are depicted in the image below.

Image by Transparent Hands via https://www.transparenthands.org/cancer-and-its-5-different-types-in-a-nutshell/.

What causes cancer?

There are many factors that can contribute to the development of cancer and different forms of cancer can arise depending on the cause. Thus, we generally cannot attribute a single cause to the development of cancer in the body. However, it is worth discussing some of the reasons why cancer may develop.

Lifestyle Factors

Consumption of tobacco and alcohol
Exposure to UV radiation
Consumption of certain food components such as nitrites and poly aromatic hydrocarbons which result from barbecued food

Work and Living Environment Factors

Exposure to asbestos fibres, tar, and pitch
Exposure to polynuclear hydrocarbons
Exposure to certain metal and plastic compounds

Bacterial and Viral Factors

Helicobacter pylori (H. Pylori)
HBV and HCV (Hepatises)
HPV (Human Papilloma Virus)
EBV (Epstein-Barr Virus)

Radiation Factors

Ionising radiation and non-ionised radiation

Drugs

Some antineoplastic agents
Some hormones
Certain medications which cause immune deficiency

Image by National Cancer Institute via https://www.cancer.gov/about-cancer/understanding/what-is-cancer.

In addition to the cancer causing factors listed above, there are biological and genetic factors which can be conducive to the development of cancer. Some biological factors are related to age, sex, skin type, and genetic defects which are inherited (What Causes).

Symptoms of Cancer

According to the Mayo Clinic, there are several general symptoms which could be indicative of the presence of cancer. Of course, these symptoms must be analyzed by a doctor but this list will provide you with a general idea.

Fatigue
Lump or thickening area under the skin
Changes in weight
Skin changes
Changes in bowel or bladder habits
Persistent cough or issues related to breathing
Difficulty swallowing
Hoarse voice
Continuous indigestion after eating
Continuous unexplained muscle/joint pain, fevers, or night sweats
Unexplained bleeding or bruising (Cancer).

Cancer Treatments

The type of cancer treatment plan that a patient receives, depends on several factors. There is not a one-size-fits-all treatment. According to the Canadian Cancer Society, some factors that are considered in determining the type of treatment that an individual will receive are the type and stage of the cancer, the patient’s personal preferences, and the patient’s age. The primary cancer treatments presently, are surgery, chemotherapy, and radiation therapy (Treatment). There are many more cancer treatments, some of which are shown in the image below.

Image by Houston Methodist via https://www.houstonmethodist.org/cancer/treatment-options/.

Conclusion

In this blog, we covered the bases of cancer. Namely, we discussed healthy cell splitting (mitosis), unhealthy cell splitting (Cancer), types of cancer and causes of cancer, and the general symptoms of cancer. Lastly, we discussed potential treatment plans for cancer patients.

Works Cited

“Cancer." Mayo Clinic, Symptoms & Causes. www.mayoclinic.org/diseases- conditions/cancer/symptoms-causes/syc-20370588. Accessed 13 Mar 2021.

Chit, Fallah. 2020, General Biology I Lecture Pack, Lecture Notes, General Biology I 101-NYA-05, Vanier College, delivered 12 Jan 2020.

“Leukemia.” Leukemia & Lymphoma Society of Canada. www.llscanada.org/leukemia#:~:text=Leukemia%20is%20a%20type%20of,survive%20better%20than%20normal%20cells. Accessed 13 Mar 2021.

“Treatment." Canadian Cancer Society. www.cancer.ca/en/cancer-information/diagnosis-and-treatment/treatment/?region=on. Accessed 13 Mar 2021.

“Tumour." National Cancer Institute. www.cancer.gov/publications/dictionaries/cancer-terms/def/tumor. Accessed 11 Mar 2021.

“Understanding Cancer.” National Institutes of Health (US); Biological Curriculum Study. NIH Curriculum Supplement Series [Internet]. Bethesda (MD): National Institutes of Health (US; 2007. www.ncbi.nlm.nih.gov/books/NBK20362/. Accessed 11 Mar 2021.

“What Causes Cancer?” All About Cancer, Cancer Society of Finland. www.allaboutcancer.fi/facts-about-cancer/what-causes-cancer/#c489640d. Accessed 13 Mar 2021.

“What Do You Want to Know About Cancer?” Healthline. 19 Feb 2016. www.healthline.com/health/cancer. Accessed 13 Mar 2021.

“What is Cancer?” National Cancer Institute. www.cancer.gov/about-cancer/understanding/what-is-cancer#:~:text=Cancer%20is%20a%20disease%20caused,are%20also%20called%20genetic%20changes. Accessed 11 Mar 2021.