Cancer: Why the Big Mama of Diseases is so Dangerous
Terry Fox started his Marathon of Hope across Canada in 1980. He ran a total of 5,373 kilometres (3,339 miles) while wearing a prosthetic leg so he could raise money for cancer research. Terry was forced to end his run in Thunder Bay, Ontario when he was diagnosed with metastatic osteogenic sarcoma. Since his death on June 28, 1981, Canadians have raised over 850 million dollars in his honour.
I’m told this story every year in school before we run around the campus within half an hour so we can get back to class. But when I ask a friend if they know why cancer is so dangerous, I’m left with nothing but a shrug 🤷♀️
That’s not exactly the reaction I’d expect if cancer is the leading cause of death in Canada.
So, why is cancer so dangerous? Heck, what is cancer? And why are people raising so much money for cancer research? Good news: you’ve come to the right place!
If you’re feeling lazy, scroll to the bottom for a TL;DR section!
How Do Cells Work?
To fully understand cancer, you should first understand the cell cycle. In its simplest terms, it goes like this:
- First, the cell is born.
- After a while, the cell gets ready to create a clone of itself.
- Then, the cell divides into two separate cells. This is called cell division and can, on average, repeat forty to sixty times per cell.
- Finally, the cell kills itself in a process called apoptosis.
Okay, cool. But what does this have to do with cancer?
What is Cancer and How Does it Start?
In a nutshell, cancer is when the cells have a genetic alteration that causes them to divide uncontrollably and ignore apoptosis. These genetic alterations are also called mutations.
These mutations occur when the DNA 🧬 inside a cell is damaged or has an error that the body cannot fix. DNA can become damaged from three factors:
- A person’s environment, such as smoking or exposure to ultraviolet rays.
- An error during cell division
- Inheritance of defected genes from a parent
Cancer cells typically have mutations in three genes: proto-oncogenes, tumour suppressor genes, and DNA repair genes.
Proto-oncogenes assist in cell growth and division. If these genes become too active or if they become mutated, they could become oncogenes, aka cancer-causing cells. This allows the cells to have more immunities and increases their growth rate.
Tumour-suppressor genes are responsible for telling a cell when to begin apoptosis, keeping cell growth at a slow pace, and occasionally repairing DNA mistakes. If these genes gain a certain mutation, it can cause the cell to divide without control.
DNA repair genes are what they sound like — genes that repair DNA. If these genes are mutated, cells can form new mutations in other genes and chromosomes.
Tumours
So, we have all these cancer cells multiplying at an alarming rate. As more and more cancer cells are created, they begin to clump together and form tumours. Cancer cells can manipulate blood vessels to attach to a tumour so it can receive oxygen and nutrients. This allows the tumour to grow bigger.
There are two types of tumours: benign and malignant.
Benign tumours stay in one part of the body. This means that doctors can remove them without much issue. Yay!
Malignant tumours, on the other hand, can spread throughout the body. How does this happen? One word: metastasis.
Metastatic Cancer
Metastasis happens when cancerous cells break off the malignant tumour. They invade the blood vessels and use them to hitch a ride as far as possible from the original tumour. Once they’ve picked a spot, the cancer cells invade the tissues of the blood vessels and create a new tumour.
Remember Terry Fox? I mentioned that he was diagnosed with metastatic osteogenic sarcoma. This means that he originally had osteogenic sarcoma, but then his cancer metastasized and went somewhere else. In his case, the cancer cells went to his lungs. The main takeaway here is that metastatic cancer always keeps the same name as the original tumour.
This is when cancer gets really scary 😱
When cancer tumours become metastasized, it is much harder to cure. There can be hidden tumours, as cancer cells can hide from the immune system. Right now, most treatments aim at stopping or slowing down the growth of tumours.
Unfortunately, once the growth rate of metastatic cancers cannot be controlled, there isn’t much we can do… yet. With technologies such as CRISPR, we’re getting closer and closer to ending cancer once and for all.
But what if there were cancers that didn’t have tumours?
Leukemia
Leukemia is blood cancer. It starts when the bone marrow (which is the place where blood cells are produced) begins producing abnormally large white blood cells. In Leukemia, there are no solid tumours involved.
Wait. Isn’t that a good thing? Doesn’t that mean the cancer can’t metastasize?
Nope.
Just like how normal cancer cells can’t stop dividing, the bone marrow can’t stop producing these giant white blood cells. Since these cells are so large, the stem cells that are residing in the bone marrow get squished to death.
Stem cells are the foundations for all the blood cells: red blood cells, white blood cells, and platelets. Therefore, when these stem cells are being killed off, the body is simultaneously losing three defence mechanisms:
- If the body is low on red blood cells, the body cannot deliver oxygen to tissues
- If the body is low on white blood cells, the body cannot fight off infections.
- If there is a shortage of platelets, the body cannot stop bleeding.
Treatments for leukemia include chemotherapy, radiation treatment, and bone marrow transfers. However, these treatments can fail or only have short-term effects.
TL;DR
- The cell cycle is the process of a cell being born, replicating itself, then dying
- Cancer happens when the DNA in cells are mutated and causes the cells to continuously divide
- Cancer cells can clump together to form tumours which can either be benign (stays in one place) or malignant (moves around the body)
- The process of cancer cells travelling through the blood vessels is called metastasis
- Leukemia is blood cancer and doesn’t have solid tumours
- Treatments for cancer aim to weaken or temporarily stop cancer from spreading, with the ultimate goal being to eradicate it
And there you have it! These are just the fundamentals of cancer and there’s still so much to explore. If this article fascinated you, I highly recommend continuing to learn more about cancer. I also hope that you consider donating money to any foundations dedicated to cancer research. As you now know, it’s for a great cause, but it also supports anyone who’s lost a loved one to cancer. Being one of those people, it fills my heart with joy when I see people contribute to these societies and it gives me hope that we will find a cure soon.
Thanks for reading!
