Everyone knows what cancer is, and unfortunately most people know someone who has been affected by cancer.
What a lot of people don’t know is what happens with cancer at a cellular level. What are cancer cells?
How do they differ from normal cells? What causes them to occur in the body? What characteristics do they have?
We have put together this helpful guide to compare cancer cells with normal cells and explain how they differ.
If you want to learn all about cancer cells and their characteristics then keep reading.
What Are Cancer Cells?
Cancer cells are normal cells that have been damaged.
The damage they have sustained prevents the cell from responding to signals in the same way as other cells, which in turn impacts the lifespan of the cell.
The cells also divide, replicating the damage and spreading those damaged cells to other parts of the body through the bloodstream and via your lymphatic system.
Sometimes, these cells group together to form tumors, either at the site of the original damaged cell or in other parts of the body.
A benign tumor may put pressure on the surrounding areas of the body, but a cancerous tumor will invade the tissue around it and can spread.
The immune system is designed to attack and eliminate damaged cells or abnormal cells.
This means that your immune system should fight the cancer cells for you, but this is not the case.
Cancer cells have a way of tricking the immune system, so it won’t try to get rid of the cancer cells.
Types Of Cancer Cells
There are many different types of cancer cells, and research into the different types is still ongoing.
Here are some of the most common types of cancer cells found in the body:
- Sarcoma – Sarcoma cancer cells affect soft tissues and blood. Sarcoma can have a negative impact on muscles, tendons, ligaments and blood vessels.
- Leukemia – These cancer cells affect the tissue that forms the blood cells. It is often identified by a high white blood cell count. The excess white blood cells gather around the bone marrow and inhibit the function of the cells as well as other bodily processes.
- Lymphoma – Lymphoma is caused by altered lymphocyte cells that are spread throughout the body via the lymphatic system to various organs.
- Melanoma – Melanoma cells develop from melanocytes. The function of melanocytes is to produce melanin. These cancer cells cause issues with the skin and the eyes.
- Myeloma – this type of cancer cell is found in the plasma cells in the body
How Are Cancer Cells Detected?
Cancer cells are able to hide out in your body for a long time without being detected.
Once your body starts to display possible symptoms, there are tests that can be done to check for the presence of cancer cells.
The cancer cells can also be picked up if you are eligible for screening.
- Lab Tests – Urine samples and blood samples can be tested to look for abnormally high or low levels of certain molecules. If the levels are off it is not enough to confirm the presence of cancer cells, but it will prompt further tests to be carried out to check.
- Imaging – There are various forms of medical imaging which can pick up the presence of cancer in the body. These include CT scans (computed tomography), MRI scans (magnetic resonance imaging), PET scans (positron emission tomography), ultrasounds, X-rays, nuclear scans, and bone scans.
- Biopsies – If there are multiple signs that point towards the presence of cancer cells in the body, then a biopsy will likely be carried out. This will allow the doctor to make a diagnosis of cancer. A sample of tissue from the affected area is taken and sent to a lab where it is examined under a microscope and tested to check for cancer cells. Taking the sample can be as simple as inserting a needle into the area, or it can be as invasive as a surgical procedure. It depends on which area of the body the sample needs to be taken from.
What Causes Cancer Cells To Occur In The Body?
There are certain factors which can increase the risk of normal cells becoming cancer cells, such as viruses and particular biological circumstances.
However, exposure to carcinogens is what causes normal cells to become cancerous.
A carcinogenic substance is something that could damage the DNA of a cell and includes radiation, certain chemicals and UV light.
Carcinogens can be found in cigarette smoke, or even in particular food additives.
The more exposure the cells have to carcinogens, the more likely it is that the DNA will be damaged.
However, it can seem to happen randomly and depend on the individual.
Someone could smoke all their life and never get cancer, and another person could smoke for 5 years and then develop cancerous cells.
When the DNA in a cell mutates due to the influence of an external factor such as a carcinogen or a virus, this is called an acquired mutation.
There are lots of different types of cancer. They are categorized by the area of the body they affect and the types of cells and how they spread.
The type of cancer caused will depend on how the carcinogen damages the DNA and how the damaged DNA is then replicated and divided.
Hereditary Genetics And The Formation Of Cancer Cells
If an acquired mutation is caused by an external factor, what is an inherited mutation?
Certain types of cancer are hereditary, which means that parents pass them down to their children.
The mutated DNA is already present in the sperm or the egg.
Once the sperm and egg become one cell, all of the cells of the body are created using the DNA from that one cell.
That means that the genetic mutation from the parent will appear in every single cell of the child’s body.
A common kind of hereditary genetic mutation that can cause cancer is linked to the tumor suppressor gene.
If the tumor suppressor gene is mutated, it can prevent the body from taking steps to detect and get rid of tumors.
What Role Does Mitosis Play In The Formation Of Cancer Cells?
The life cycle of a cell is split into different stages – interphase, mitosis, cytokinesis, and then cell death.
Interphase is when the cell grows in preparation for mitosis.
Mitosis is when the cytoplasmic matter of the cell (including the organelles and the DNA) is split into two and moved into position ready for the cell to divide.
Cytokinesis is when the cell is divided into two daughter cells, and cell death is the end of the cell life cycle.
Cancer is sometimes referred to as the disease of mitosis, because it is in the mitosis phase of the cell life cycle that cells can become cancerous.
DNA is made up of chromatids – threads of DNA in sister pairs.
These chromatids are condensed into dense coils of DNA called chromosomes.
These chromosomes are found in the nucleus of the cell, and they contain all of the genetic information – this is why the nucleus is called the brain of the cell.
When a cell divides, the chromosomes are copied and then lined up on either side of the cell equator.
If the chromosomes do not align themselves correctly, they will not be split equally between the two daughter cells.
This means that the daughter cells will not have the same genetic information as the parent cell.
One daughter cell will have too many chromosomes, and the other will have too few.
This can lead to a multitude of health problems including conditions like Down’s Syndrome and diseases like cancer.
The damaged DNA that the cell is given can impact the type of cancer that develops and how aggressive it is.
For example, if the daughter cell with too many chromosomes contains genetic information that is geared towards a certain biological function, that function will then present itself in an exaggerated way in the body.
If the DNA is geared towards fast cell reproduction, then the cancer will spread much more rapidly.
Cancer Cell Characteristics
So how do cancer cells differ from normal cells? What characteristics do they have?
Cancer cells have a different shape to normal cells.
The shape of a normal cell is usually relative to the specialized function of the cell, but once a cell becomes cancerous it will change shape and resulting daughter cells will also have an abnormal shape.
The shape of the nucleus will also be affected, as this is where the DNA is stored.
The nucleus is usually smooth, but the nuclei of cancerous cells have bulges (also called blebs).
The normal life cycle of a cell is growth, division, and then death.
When a cell dies it is called apoptosis, or sometimes shrinkage necrosis. The lifespan of a cell depends on its function.
Cells are not supposed to live forever, as the body is able to regenerate and new cells are constantly being made.
Cells receive a signal from the body which initiates the process of apoptosis.
Cancer cells do not respond to this signal due to the damaged DNA.
Instead of dying, cancer cells divide and multiply again, spreading more damaged cells around the body.
But how does the damaged DNA continue to replicate? Normal chromosomes have telomeres which are found on the end of the DNA coil.
These shorten every time the DNA is copied, which means there is a limited number of times the DNA can be replicated.
The damaged chromosomes of cancer cells do not have telomeres, which means the damaged DNA can be copied and split between daughter cells an infinite number of times.
Cancer cells are not able to repair themselves unlike normal cells.
This means that they cannot repair the damaged DNA, so it continues to be replicated and spread to all of the daughter cells being created from the original parent cell.
This is also related to the increased life span of cancer cells.
They are unable to perform the same checks as normal cells to establish whether the cell is damaged. This means that the cell cannot tell when it is time to die.
Once a normal cell is damaged and becomes a cancer cell, it can no longer perform the function it was originally created for.
This is because the DNA, the genetic information, has been damaged.
When the cell divides and multiplies the damaged DNA is replicated, which means the daughter cells cannot perform their cell function either.
This means that the function of the part of the body the cell is affecting will become more inhibited as the cancerous cells spread.
Reduced cell function is also linked to the abnormal shape of cancer cells.
If the shape of the cell is directly related to the function that the cell performs then when cancerous cells become misshapen this will cause a problem.
For example, the shape of red blood cells allows them to flow smoothly through narrow blood vessels.
If the shape is compromised, the blood cells will not be able to flow effectively around the body.
The rapid growth rate of cancer cells also prevents them from carrying out their function.
Normal cells will mature slowly, which allows them to develop into specialized cells with a specific purpose.
Cancer cells grow so fast that they cannot specialize, which prevents them from fulfilling the purpose they were originally created for.
In order for cells to grow, divide, and to perform their functions in the body, they need energy.
This energy comes from cell food such as glucose and oxygen etc.
The Mitochondria, an organelle within the cell, converts these molecules into a form of chemical energy called adenosine triphosphate.
This is done through anaerobic respiration, and it gives the cell the energy it needs.
Cancer cells have been found to have a lower metabolic rate than normal cells.
This means that they require less energy to grow and divide, so the cell needs less food or fuel and does not need to create as much energy.
This makes it much easier for cancerous cells to divide and multiply and ultimately spread throughout the body.
Cancer cells use a lot more glucose than oxygen to create their energy.
The more cancerous cells you have in your body, the more glucose they will take, which can lead to weight loss and low blood sugar levels.
Certain cancer cells can also act as parasites, absorbing glucose and oxygen from the healthy cells around them in order to create the energy they need.
This not only accelerates the rate of their growth, it also inhibits the growth, division and cell function of the healthy cells.
This prevents those areas of the body from being able to regenerate, repair and heal.
Another method cancer cells use to get more fuel for growth is angiogenesis.
Simply put, the cell produces the right environment for more blood cells to form, which increases the amount of glucose being brought to the cell.
However, the increased amount of blood cells increases the likelihood of the cancerous cells spreading through the body in the bloodstream.
This contributes to metastasis – the formation of a secondary tumor in a different part of the body from the original site of the cancer.
Around the site of a tumor, cancel cells will actually recruit other cells to create more blood vessels for them too.
This enables the tumor to continue growing rapidly as it will receive more oxygen and glucose.
Normal cells have adhesive properties which are known to assist with multiple cell process including cell growth.
Cancer cells have less of the surface molecules which allow adhesiveness, such as the molecule E-Cadherin, yet this does not slow down their growth rate.
However, the fact that cancer cells are less adhesive than normal cells means that they can travel around the body more easily, allowing the cancer to spread.
Normal Cell Characteristics
In comparison to cancer cells, normal cells have the following characteristics.
Normal cells have a regular, uniform shape which is specific to their specialized function.
Normal cells can control their growth so that new cells are only created as and when they are required.
Normal cells are also able to perform protein checks to see if there is any DNA damage.
Once DNA damage is detected, the cell knows that the telomeres have become shortened and the DNA is no longer able to be replicated.
This triggers the beginning of the death of the cell.
New cells are constantly being created to allow the body to regenerate, grow, heal and function. The immune system gets rid of any rogue cells with damaged DNA.
Normal cells grow slowly which allows them to mature into specialized cells.
These cells have specific functions within the body, which keeps the body running smoothly.
Normal cells create the chemical energy needed to carry out their functions by processing glucose and oxygen.
Certain molecules and proteins are transported to the cell and within the cell to the organelles that need them.
Normal cells have an adhesive surface which ensures that they remain in the correct location in the body.
Observing Cancer Cells Under A Microscope
Different microscopy techniques have been used to view and study the different types of cancer cells.
The technique you use will depend on which type of cell you are looking at.
For example, lymphoma cells can be viewed using peripheral blood films whereas squamous cells can be seen under a light microscope.
If you want to view squamous cells (which cause carcinoma) using a confocal microscope then this is what you will need.
Equipment and Requirements
In order to use this method you will need the following:
- A confocal microscope
- A clean glass slide
- Wooden sticks or cotton swabs
- A sample of squamous cell carcinoma from the buccal mucosa
- Acridine orange stain
- Distilled water
- Phosphate buffer solution
- 100% alcohol
- 1% acetic acid
These are the steps you will need to follow:
- Step One – Use a cotton swab or a wooden stick to wipe the sample onto a clean glass slide.
- Step Two – Use the alcohol to fix the sample and leave it for 15 minutes.
- Step Three – Use the acetic acid to rinse the slide for no more than a few seconds
- Step Four – Wash the slide in distilled water for 30 seconds. Change the water then wash it again.
- Step Five – Use 0.01 of acridine orange stain to stain the sample for around 3 minutes
- Step Six – Use the phosphate buffer solution to de-stain the glass slide for around one minute.
- Step Seven – Add a drop of the buffer solution to the glass slide
- Step Eight – View the slide under the microscope. You should be able to see the abnormality of the nucleus as it will be broken up around the cell and it will appear green in color.
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