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Today, 1 in every 3 women and 1 in 2 men in the United States are diagnosed with cancer at some point in their lives. Cancer is so prevalent that there is a high chance that every person in the United States knows at least one other person who has been afflicted with cancer. Though cancer is almost always damaging to the body, the level of harm caused by cancer cells varies depending on whether the tumor is benign or malignant. In this post, we will explore what it means to have cancer and contrast what it means for a tumor to be benign versus malignant.
What is Cancer?
In essence, cancer is a disease in which some of the body's cells die uncontrollably and sometimes spread to other parts of the body. Because cells can grow almost anywhere in the body, cancer can also start anywhere in the body.
In normal human cells, these cells grow and multiply to form new cells as the body needs them. For instance, if a baby grows a few inches taller, that means new cells have been formed. Also, if some of the cells in a human body grow old it will be replaced by new cells.
However, in some cases, abnormal or damaged cells multiply usually due to faulty genes. There are many types of genes that can contribute to cancer, including the following:
Proto-oncogenes: When normal cells genes are altered in such a way that they become more active than normal causing cells to multiply when they should have died.
Tumor Suppressor genes: Genes that are involved in controlling cell growth and division are altered so that cell growth and division is no longer suppressed, causing the cells to grow out of control.
DNA repair genes: Mutations in the gene that fixes damaged DNA causes mutations to appear in the genes of other DNA itself. All of the mutations taken together can cause a tumor and abnormal cell growth.
When these cells grow, they develop lumps of tissue known as tumors. Because they grow out of control, these cancerous cells sometimes invade nearby tissues and can even be life threatening.
How Are Tumors Formed?
So how exactly do these cells become "abnormal" in order to create cancerous tumors? In order to understand, you must know that genes have a DNA sequence that codes for the cell. Millions of these coded cells then make tissues.
Diagram of the Biological Levels of Organization in a complex multicellular organism. Provided by Vecteezy and Dreamtime.com
Almost all cancers are caused by mutations in genes. These gene mutations can happen for a variety of reasons:
Inherited: Often, genes are inherited from relatives. However, if parents have/had cancer it doesn't mean their child will get cancer because different genes are expressed in different people at different times. And there is always the chance that the child didn't inherit the gene. But the same goes if the parents did not have cancer, because they may still have a mutated gene but not have expressed it and therefore the child would still be at risk of cancer.
Developed: Normally, the body is supposed to eliminate cells with damaged DNA before they become cancerous, but as the body grows older, sometimes the body is not able to carry out this elimination. In fact, almost half of all cancers diagnosed are in people 66 or older, while those under the age of 20 make up only 1% of all cancer cases.
Harmful Substances: Lastly, some cell mutations are caused by harmful substances such as alcohol or UV light. UV light generates singlet oxygen (a type of reactive oxygen) and/or hydrogen peroxide, which oxidizes (the DNA loses a hydrogen) to damage the DNA when it absorbs the photons emitted from the UV light. Similarly, alcohol prevents the transcription and translation of DNA by causing lesions that are highly toxic (this process is called interstrand crosslinking or also known as ICL).
Normal vs. Cancer Cells
There are certain characteristics that differentiate cancer cells from normal cells. Here are some differences between cells that have cancer compared to those of normal cells:
Benign vs. Malignant
Usually, when people hear about cancer, they immediately think about malignant tumors that spread throughout the body. Though this is sometimes the case, most cancers are actually benign or noncancerous. Even though a benign tumor doesn't pose nearly as much risk as a malignant tumor, it may still be harmful, especially if left undetected for a long time. A doctor or health care provider can determine if the tumor is cancerous through biopsies (examining a sample of cells through a microscope) or imaging tests (ex. MRI, CT Scan, etc.).
Benign Tumors
Benign tumors are noncancerous, meaning these mutated cells do not spread to other parts of the body or invade other tissues. Though these tumors still have mutated DNA, the tumor cells are generally contained in one spot. These tumors can also have blood vessels that grow in them, but significantly less than a malignant tumor, making this type of tumor easier to surgically remove.
However, even benign tumors can become dangerous in some cases. These tumors can grow very large if left untreated, sometimes weighing up to several pounds! If the tumor is located in a critical spot such as the brain or the trachea (our airway), then even benign tumors can be dangerous. These tumors can push on these vital organs and cause paralysis, strokes, airway obstruction, and, in rare cases, death. Sometimes benign tumors can also cause excess hormone production, which can also affect the body, including weight gain, infertility, etc.
On the flip side, sometimes it may not even be a problem to leave benign tumors in the body as long as there is no organ that is being severely damaged. In most cases, benign tumors are merely observed and, if needed, either for cosmetic or health purposes, surgically removed.
Some types of benign tumors include:
Fibroids
Lipomas
Adenomas
Hemangiomas
Malignant Tumors
Malignant tumors, on the other hand, are almost always invasive. The mutated cells spread so that they invade other tissues and cause cancerous tumors in other parts of the body as well. For instance, if the cancer first develops in the pancreas, it may spread to the stomach and other vital organs. This spread is known as "metastatic cancer."
The spread of cancer is primarily determined by the stage of the disease. If the cancer is in its early stages, it has most likely not spread. If the cancer is at Stage 4, it has most certainly spread to other parts of the body and is far more hazardous than if it is in Stage 1, which can be treated effectively. The following is a brief explanation of each stage of cancer:
Stage 1: the cancer hasn't spread anywhere else in the body
Stage 2: the cancer has grown but hasn't spread
Stage 3: the cancer is larger and may have spread to the surrounding tissues and/or glands
Stage 4: the cancer has spread from where it started to one other body organ, cancer is classified as "metastatic" or "secondary"
Doctors and medical professionals often figure out if the cancer has metastasized if it has the characteristics of a different tissue. For instance, if a doctor finds a cancerous tumor in the lung that is showing characteristics of a breast cell, then it can be inferred that the cancer from the breast has metastasized or spread to the lung. However, additional imaging would need to be done to confirm this assumption.
Also, because malignant tumors survive on many blood vessels in the body, it is sometimes hard to remove all of the cancer cells through surgery, and therefore other methods such as chemotherapy or radiation therapy (generally not used anymore as it is an older technique) are used to get rid of the remaining cancer cells.
Here is a quick table of the differences between benign and malignant tumors:
Can Benign Tumors Turn Malignant?
Though it is very rare, some benign tumors can turn malignant. However, precancerous tumors can become malignant if left untreated for a long time. Some examples of precancerous tumors include colon polyps, ductal carcinoma (a type of breast cancer tumor), actinic keratosis (a skin condition), etc. These originally benign tumors can be removed through surgery as a preventative measure against tumors becoming malignant.
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