This article discusses cancer cells.
It explains how cancer cells develop and how they differ from normal cells.
vitanovski / Istockphoto.com
What Is Cancer?
vitanovski / Istockphoto.com
Cancer is a disease that pops up if cells become abnormal and grow out of control.
Normal cells growand then diewhen they are given signals to do so.
Cancer cells ignore these signals and continue to multiply.
Types of Cancer Cells
There are as many types of cancer cells as there are types ofcancer.
Carcinomas
Carcinomas are cancers that arise in epithelial cells that line body cavities.
Unlike some other cancers, leukemia cells do not bind together to form a tumor.
Lymphomas can develop in different types of white blood cells known as B-cells, T-cells, and NK cells.
They can begin anywhere in the body and feed on nutrients in the lymph fluid.
They occur when a plasma cell becomes abnormal, then divides to replicate, forming myeloma cells.
Myelomas collect in the bone marrow and soft tissue to form a tumor.
When it affects several bones, it is known as multiple myeloma.
It can also affect other tissues and organs, such as the kidneys.
How Do Cancer Cells Form?
These changes may be inherited or due to external factors, like smoking or exposure to ultraviolet rays.
Mutations can also be completely random.
Cancer cells appear through a series of genetic andepigenetic(or environment-induced) changes.
These stages may include hyperplasia (enlarged) and dysplasia (growing abnormally) before cancer.
Sometimes, this process is described as differentiation.
Early on, a cell may look much like normal cells of that organ or tissue.
As the progression continues, the cell becomes increasingly undifferentiated.
This is why sometimes the original source of cancer cannot be determined.
Recap
Cancer cells form when genetic mutations cause cells to behave abnormally.
The mutations can be inherited or be sparked by exposure to carcinogens like tobacco smoke or ultraviolet rays.
In some cases, mutations can occur randomly.
Cancer is a disease that is sparked by a combination of factors (multifactorial).
Lifestyle and environmental factors will play a role, too.
And they tell cells when to die.
Most cancer cells have mutations in both oncogenes and tumor suppressor genes, which lead to their behavior.
Cancer cells continue to grow (reproduce) even when further cells are not needed.
They also ignore signals that tell them to stop dividing and continue to multiply instead.
Cancer cells do not respond to these signals and extend into nearby tissues, often with finger-like projections.
This is one reason why it can be difficult to surgically remove a cancerous tumor.
Immortality
Most normal cells, like humans, have a limited lifespan.
When they reach a certain age, they die.
Cancer cells, in contrast, have developed a way to defy death.
At the end of our chromosomes is a structure known as atelomere.
Every time a cell divides, its telomeres become shorter.
When the telomeres become short enough, the cells die.
In this way, they become immortal.
This is because cancer cells evolve to avoid detection.
This process also lies at the crux of the new field of cancer treatment known asimmunotherapy.
The word “cancer” comes from the Greek wordcarcinos,which means crab.
Cancer Cells Change
Once cancer has formed, the cells don’t remain the same.
Rather, continued mutations may occur.
This is why resistance develops to chemotherapy and targeted therapy drugs.
The cancer cell develops a mutation that allows it to bypass the damaging effects of these treatments.
Cancer cells' ability to change is very important in treatment.
This would require a different treatment.
It also helps explain why cancer cells in different parts of a tumor may be different.
This is referred to as “heterogenicity” and is important in diagnosis and treatment.
An often-confusing condition iscarcinoma-in-situ(CIS).
It consists of cells with abnormal changes found in cancer cells.
Since CIS can turn into cancer, it is usually treated as early cancer.
Summary
Cancer cells appear through a series of genetic and environment-induced changes.
But this is just the beginning.
Once cancer has formed, the cells don’t remain the same.
Rather, continued mutations may occur.
This is why resistance develops to chemotherapy and targeted therapy drugs.
US National Library of Medicine.
National Cancer Institute.What is cancer?
National Cancer Institute.Cancer stat facts: leukemia.
National Cancer Institute.Cancer stat facts: non-Hodgkin lymphoma.
National Cancer Institute.Cancer stat facts: myeloma.
Medline Plus.What does it mean to have a genetic predisposition to a disease?
2020;5(1):28. doi:10.1038/s41392-020-0134-x
American Cancer Society.Changes in genes.
2018;16(3):e2002930.
Johns Hopkins Medicine.Overview of cancer.
Adjiri A.Tracing the path of cancer initiation: the AA protein-based model for cancer genesis.BMC Cancer.
2018;18(1):831. doi:10.1186/s12885-018-4739-1.
2018;32(19-20):126784. doi:10.1101/gad.314617.118
Peters GJ.Cancer drug resistance: a new perspective.
CDR.2018;1:1-5. doi:10.20517/cdr.2018.03.
American Cancer Society.Treatment options for testicular cancer, by bang out and stage.
