NURS 530 Discussion The Process by Which Cancer Originates

NURS 530 Discussion The Process by Which Cancer Originates

NURS 530 Discussion The Process by Which Cancer Originates

DQ1 Select one of the following discussion prompts to address:

Describe autoimmunity and the process by which the body develops a hyperimmune or hypersensitive reaction to its own tissues. Consider lupus. It has been found that those living with lupus are at higher risk for other autoimmune diseases such as rheumatoid arthritis. Explore this interrelationship, known as overlap diseases, in the following website, Molly’s Fund and discuss the implications for care.

Describe active versus passive immunity and provide an example of each. Define antibody or immunoglobulin and describe the five molecular classes of immunoglobulins and their function(s) in the body by providing a pathologic example for an increase of each immunoglobulin (e.g., IgE—parasitic infection). Why are some viruses inaccessible to antibodies after initial infection?

Describe and discuss transmission, pathogenesis, clinical manifestations, treatment and prevention of HIV/AIDS.

DQ2 Select one of the following discussion prompts to address:

Describe how normal cells go through the process of transformation into cancer cells. How is this process different from DNA mutations associated with genetic disease? Review this article on genetics and identify how the mutations differ.

Stress and Disease: Describe the physiologic effects on body systems of increased cortisol levels released during the stress response.

Review the current research evidence from credible, scholarly sources and summarize the results of the effects and health risks of electromagnetic radiation (from cellular and cordless telephones, microwaves, computers, fluorescent lights, radar, and electronic equipment).

What Is Cancer?

To understand oncogenesis, it helps to understand what a  really is. Cancer is a name for a group of diseases that share some similarities but have some distinct differences, both in terms of the specific changes that have occurred and the possible treatment options. For instance, a breast cancer is different than a cancer arising from another part of the body, such as colon cancer.

However, even with cancer that occurs within a single organ, there are many different subtypes of cancer which may respond differently to treatments.1 There are many different , and more subtypes will probably be discovered as scientists learn about the specific differences that can occur.

What Are Cells?

Cells are the small individual working units that compose the tissues and organs of your body. Each cell contains its own copy of , the genetic material you inherit from your parents. Different cells have different purposes and do different jobs, depending on where in the body they are found. Inside every cell is the machinery it needs to copy its genetic material and divide to make a new “daughter” cell. But this should happen only under specific, controlled circumstances.

As an example, it’s normal for certain types of bone cells to grow and divide in children as they become taller. Cells in your skin normally replicate themselves as well, to replace the old, dead skin cells that are continuously shed. Certain immune cells should replicate themselves as part of your immune response to infection. But other cells in your body shouldn’t replicate and divide under normal circumstances. For example, muscle cells do not normally replicate themselves in adults.

Then, daughter cells of the abnormal cells will share this same tendency to divide—this creates even more cells. In some cases, the cancer cells may invade other areas and interfere with the functions of normal cells. This can lead to the symptoms of the specific cancer, and it may cause death if untreated.

Genetic Mutations

In certain circumstances, something may damage the DNA that encodes one of these important proteins. Sometimes, the cell manages to repair the DNA successfully without a problem. Other times, however, the DNA might not be correctly repaired, leading to what is known as a genetic mutation. This mutation is then passed down to every new daughter cell. The protein made from the mutated DNA may not work as it normally would.

Though it may not be a big issue at first, the cell may experience more damage to other important parts of the DNA—other genetic damages, or “hits.” A cancer occurs when a group of cells has lost a critical mass of these feedback mechanisms, and they are replicating themselves without proper cellular controls. This happens through the process of oncogenesis, which may occur over many years before a fully developed cancer is discovered.2 Other genetic hits may make the cancer even more dangerous by enabling it to better invade tissues or achieve a blood supply. Other genetic “hits” may prevent the cells from going through the normal processes of cellular death (called “apoptosis).

Some of the “hits” that occur are not due to changes in the DNA itself, but due to changes in molecules attached to the DNA or to its packing material. These are called “epigenetic” changes. For example, the addition of a molecule at a specific location might increase how often a specific gene is made into a protein. Or it might do the reverse. Depending on the gene involved, this might contribute to the process of oncogenesis.2

Through this complex process, the cancer tissue is prone to invade nearby tissue, which may impair its function. It also may metastasize. That means, that the cancerous cells can spread through the blood or lymph system and start to grow in other parts of the body, like the lungs or the liver.

What Is the Difference Between a True Cancer and a Benign Tumor?

One important characteristic of a true cancer is this ability to invade nearby tissue or potentially  throughout the body.

Benign tumors share some characteristics with cancer. They may have picked up some genetic “hits” that cause them to behave a little differently than normal tissue. They may also divide in some uncontrolled ways. However, they do not have as many severe genetic and epigenetic hits as a cancer.3 By definition, a benign tumor is not prone to massive spread in the body. In rare circumstances, a benign tumor goes on to become a malignant one, a true cancer, but usually, this doesn’t happen. However, some benign tumors still sometimes cause problems. This might happen, for example, if one was pressing on a nearby important blood vessel.

What Causes Cancer?

Cancers are a complex group of diseases with a complicated set of causes. Anything that can damage the DNA or cause certain epigenetic changes can increase one’s risk of getting cancer.

Carcinogens

Such substances that can damage the DNA are called . DNA damage to specific genes can lead to the process of oncogenesis. For example, excess exposure to ionizing radiation from the sun can increase one’s risk of getting skin cancer. Exposure to DNA-damaging substances in cigarettes can increase one’s risk of lung and other cancers. Certain substances don’t cause direct DNA damage, but instead, alter the epigenetic coding in a way that makes cancer more likely.

In most cases, it’s thought that a variety of factors must come together to cause a cancer.1 In other words, a person must experience more than one genetic or epigenetic alteration to develop the disease. By the time a cell is cancerous, it has acquired a number of genetic mutations that it continues to pass on to its daughter cells as it divides.

Disruptions in Cellular Function

Factors that stress cells and disrupt normal cellular function can also increase one’s risk of cancer. For example, in people with gastroesophageal reflux disease, certain cells in the esophagus are exposed to acid from the stomach. This can lead to , a pre-cancerous condition in which cells are not quite behaving normally but aren’t yet acting like fully developed cancer cells. These cells sometimes, but not always, go on to develop a cancer.4 There is growing evidence that this and other kinds of chronic inflammation may increase one’s risk of cancer as well.

Viral Infections

Infection with certain types of viruses can also increase one’s risk of cancer, though not everyone with the virus will develop it.5 These viruses can insert genetic material into normal cells that can contribute to cancer development. In other cases, they may disrupt the immune system, thus increasing one’s risk of cancer.

Family History

One’s family history is also an important factor. People who have inherited certain genes from their parents are more susceptible to getting cancer. That’s because certain variants of particular genes may be more susceptible to cancer formation. For example, the  makes a protein that is important for normal DNA repair.6 People born with certain variations of this gene may be more likely to develop certain types of cancers compared to people who don’t have the mutated version.

Age

Age is also a major risk factor. Except for certain cancers that almost always occur in children, the risk of most cancers increases with age.7 That’s because people normally accumulate mutations in their genes over time. With greater age, there is an increased risk that one of your cells will get enough of the wrong kind of “hit” to get cancer.

It’s important to note that some people get cancer even if they don’t have a family history of cancer, and even if they aren’t exposed to any known major carcinogens.

Prevention Techniques

Generally speaking, one can decrease the risk of cancer by lowering one’s exposure to these possible genetic and epigenetic “hits.”

Certain screening procedures can also make sure that precancerous areas of the body are detected early when they are easily removed.

Cancer Treatment and Oncogenesis

Oncogenesis has already occurred in people diagnosed with cancer, and this process cannot be reversed. Many types of cancer treatments focus on removing cancerous cells from the body. For example, a surgeon may be able to remove all cancerous cells from the body, curing the person of the disease. Other treatments, like chemotherapy, may focus on killing the cancerous cells. Such treatments don’t work by stopping oncogenesis, but by removing cancerous cells from the body completely.

However, other types of cancer treatments prevent cancerous cells from being as dangerous to the body. For example, certain treatments stop the cancer’s ability to form new blood vessels (). Other treatments may slow a cancer’s growth in other ways. By slowing the cancer’s growth, they may help the cancer from getting further genetic hits that might make it more difficult to treat. In this sense, these treatments may slow or even stop the process of oncogenesis. However, most people will also need other treatments that directly remove the cancer from the body.