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Cancer and Homeostasis

Cancer and Homeostasis

Description:

This lesson will identify what causes cancer, how your immune system attempts to fight cancer and various treatments of cancer. This lesson will also investigate the affect cancer has on the body's ability to maintain homeostasis.

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Tutorial

What's Covered

This lesson will look cancer and its relation to homeostasis by covering:

  1. Formation and Growth
  2. How Cancer is Fought
  3. Types of Cancer

1. Formation and Growth

Cancer is the uncontrolled cell division, which can form a tumor and lead to metastasis. Normally, cells divide at a rate to replace old cells and maintain homeostasis which is controlled by the cell's DNA. When DNA becomes mutated, it can cause these cells to divide uncontrollably. When a cell will starts to divide uncontrollably, it will form this mass of abnormal cells called a tumor. Cells in a tumor can break off and float down the bloodstream, planting themselves somewhere else in the body; called metastasis.

Terms to Know

    • Cancer
    • A condition caused by the uncontrolled division of cells.
    • Metastasis
    • The spreading of cancerous cells from one site in the body to another.
    • Tumor
    • A mass of abnormal cells formed from the uncontrolled division of cells in the area.

Causes of cancer include:

  • Cancer can be hereditary. A person could have a higher risk of cancer if someone in their family has had it.
  • Viruses
  • Chemical carcinogens are cancer-causing agents, such as smoking.
  • Radiation
  • Suppression of the immune system

Term to Know

    • Carcinogen
    • A substance that can cause cancer.

An oncogene is a gene that does not respond to normal controls that regulate the division of a cell. Normally, our cells have regulated cell division controlled by DNA. Sometimes, a certain gene doesn't respond to those normal controls, and it will start to divide uncontrollably. An oncogene in itself does not cause cancer. In order for cancer to develop, it requires the mutations of at least one tumor suppressor gene. Tumor suppressor genes help prevent cancer by slowing or stopping cell growth.

Terms to Know

    • Oncogene
    • A gene that does not respond to the normal signals for cell division.
    • Tumor Suppressor Gene
    • A gene that acts to stop or slow abnormal cell growth.
IN CONTEXT
So if a person has two controls to stop the growth of cancer, how do people still get it?
Let's say someone has an oncogene that's not responding to normal controls and the cells are starting to divide very rapidly. Their tumor suppressor genes will normally help to stop that by slowing or stopping the cell growth or division. If this same person’s tumor suppressor genes is mutated,however, it's not going to be able to do its job, and it's not going to be able to stop or slow cell growth or division; causing the formation of tumors.

Angiogenin is a growth factor secreted by cancer cells that causes more blood vessels to grow around the tumor. This supplies a tumor with oxygen and nutrients to grow.

Term to Know

    • Angiogenin
    • A substance secreted by cancerous cells that encourages blood vessels to grow around the tumor to provide necessary oxygen and nutrients for growth.

2. How Cancer is Fought

The body has some defenses against cancer once it develops. Cell-mediated immune responses work to attack cancer cells. This is a part of the immune system that works on abnormal and compromised cells. Cell-mediated immune response involves invaders inside cells, cancerous cells, and other abnormal cells. Cytotoxic T cells and NK cells are a part of cell-mediated immune responses.

  • Cytotoxic T cells will cause apoptosis of irregular cells, which is the programmed cell death. It will target these cells, and those cells will eventually be killed.
  • NK cells attack and kill irregular cells.

Terms to Know

    • Apoptosis
    • Self destruction of cells brought on by cytotoxic T cells.
    • NK Cells (Natural Killer Cells)
    • Lymphocytes which help kill abnormal cells of the body including cancerous cells.

There are treatments for cancer that can help kill it when our body’s own defenses are not enough. Treatment of cancer generally involves:

  • Chemotherapy
  • Radiation
  • Surgery

Terms to Know

    • Chemotherapy
    • A form of treatment for cancer patients in which chemicals are used to try to kill cancerous cells.
    • Radiation Therapy
    • A form of treatment for cancer patients in which radiation is used to try to kill cancerous cells.

There is research currently being done on angiogenin, the growth factor that's secreted by cancer cells that supplies blood vessels to the tumor. This research is being done to try and find a way to stop its production or secretion by those cancerous cells. If angiogenin wasn't secreted, then blood vessels wouldn't grow around the tumor, and the tumor would not be supplied with nutrients it needed. Effectively, the tumor would end up starving.

Term to Know

  • Angiogenin
  • A substance secreted by cancerous cells that encourages blood vessels to grow around the tumor to provide necessary oxygen and nutrients for growth.

3. Common Types of Cancer

Melanoma is a form of skin cancer. Melanocytes are cells that are found in the deepest layer of the epidermis that can be affected by things like UV light or UV radiation. If they are exposed to UV light or UV radiation, the DNA within them can become mutated, causing cancer.

Other types of cancer can include:

  • Lymphoma is cancer of the lymphatic system.
  • Adenocarcinoma is cancer of gland tissues.
  • Leukemia is cancer of the bone marrow
  • Sarcoma is cancer of connective tissues

While these are some common types of cancers, there are many others.

Summary

Cells naturally divide and reproduce to supply new cells when old cells die. This maintains homeostasis in our bodies. Sometimes, though, mutations occur that allow for the formation and growth of cancer. When there is a mutation in the DNA of a cell it can start to divide uncontrollably. This is an Oncogene. When there is a mutation in the tumor suppressor gene as well, that is when cancer can form. Angiogenin is growth factor that causes blood vessels to supply a tumor with the nutrients it needs to grow. Our bodies do have a type of immune response to fight cancer. The cell mediated response will seek out and destroy abnormal cells. There are also treatments such as chemotherapy, radiation, and surgery that can help treat cancer. New research is constantly being done on new treatments. There are many types of cancer, but some common ones include melanoma, lymphoma, adenocarcinoma, leukemia, and sarcoma.

Keep up the learning and have a great day!

Source: Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

TERMS TO KNOW
  • Carcinogen

    A substance that can cause cancer.

  • Angiogenin

    A substance secreted by cancerous cells that encourages blood vessels to grow around the tumor to provide necessary oxygen and nutrients for growth.

  • Tumor

    A mass of abnormal cells formed from the uncontrolled division of cells in the area.

  • Metastasis

    The spreading of cancerous cells from one site in the body to another.

  • Tumor Suppressor Gene

    A gene that acts to stop or slow abnormal cell growth.

  • Oncogene

    A gene that does not respond to the normal signals for cell division.

  • Radiation Therapy

    A form of treatment for cancer patients in which radiation is used to try to kill cancerous cells.

  • Chemotherapy

    A form of treatment for cancer patients in which chemicals are used to try to kill cancerous cells.

  • Cancer

    A condition caused by the uncontrolled division of cells.

  • NK Cells (Natural Killer Cells)

    Lymphocytes which help kill abnormal cells of the body including cancerous cells.

  • Apoptosis

    Self destruction of cells brought on by cytotoxic T cells.