Cancer: uncontrolled division of cells.

Can cancer be inherited?

There are over 200 different kinds of cells in the human body. These cells are continually dividing, under the control of the genes within each cell. The length of time between cell divisions differs widely from one type of cell to another. Some cells in the intestine divide twice each day, while liver cells might divide only once every 18 months.

The DNA in cells code for the production of an estimated 100,000 different proteins in humans. Some of these proteins are responsible for the chemical signals that control growth and division of cells. If the code, or the proteins themselves are malformed, the result can be a cancer cell.

Anything that damages cells might cause cancer.

Over the course of your lifetime, the DNA of a single gene may be damaged several billion times. Therefore, a single "injury" is not the cause of cancer. Something much more significant must occur. About 20 human genes have been identified that, when altered, can lead to the more common types of cancer.

Oncogene - a gene that causes cancer or other uncontrolled cell division.
Proto-oncogene - a gene that, when altered by mutation, becomes an oncogene.
Anti-oncogene - a gene that suppresses tumor growth.

  Watch News flashes on Cancer

Carcinogen an agent that leads to the production of a cancer cell. These include, but are not limited to, chemicals like formaldehyde and benzene, radiation, tobacco, and some viruses. Short video clip on carcinogens: Mutagen a substance that causes mutations to occur in a cell.

Tumor - a mass of cells resulting from uncontrolled, abnormal cell division.

Types of tumors:

Benign: the tumor cells remain attached to the parent tumor.

Benign comes from the Latin work benignus, meaning "good".

Malignant: the tumor cells metastasize.

Cells metastasize when they break away from the parent tumor and spread to other parts of the body, where they begin forming new tumors. Malignant tumors are categorized by the types of tissues they affect:

Carcinoma - occurs in skin and nerve cells.

Three types of skin cancer:
1. malignant melanoma
2. Basal Cell Carcinoma
3. Squamous Cell Carcinoma
Sarcoma - occurs in bone and muscle cells.
Lymphoma - occurs in lymph cells.

Leukemia - uncontrolled production of white blood cells.

Oncologist

Treatments for cancer: Surgery - physically removes the cancer cells from the body. Chemotherapy chemicals taken internally to kill cancer cells. Radiation therapy - exposing the tumor to radiation to kill cancer cells.

Day 2 Assignment - Mutations and Cancer
This assignment must be turned in by the end of class today to receive credit.
Scoring criteria

1. Over the course of your life time, how often is the DNA of a single gene damaged ? Are these the cause of cancer? Explain
2. Summarize in your own words, how normal cells and cancer cells behave differently.
3. Cancer cells go through different stages of development. What part is usually responsible in killing the organism/patient? (hint: see first link on this page)
4. View the animation video's at this site: National Cancer Institute and complete the following questions.
   • What keeps the rate of cell division equal to the rate of cell death?
   • Describe a tumor.
   • What is the cell cycle clock?
   • What type of genes play a major roll in regulating the cell cycle?
   • What is the function of tumor suppressing genes?
   • How are the answers in the previous two questions related?
   • What important mile stone came in the 1970's about cancer?
   • How do mutations affect proto-oncogenes and tumor suppressing genes?

Honors biology: complete the above section along with this section.

1. View the news flash link (above) on cancer and give a brief summary of each episode.

Day 3-4

Tobacco is not only a carcinogen, it is a teratogen. What is a teratogen?

Day 3-4 Assignment - Mutations and Cancer
Two days to complete plus presentation day
Scoring rubric

1. Did you know that Arizona has a high rate of skin cancer related to UV light?
2. What do you know about skin cancer?
3. How many people has it affected and how many people has it caused to die?

Many people are dying from skin cancer and based on information about skin cancer a proposed statute has been put forward that would require that young people protect themselves from UV radiation. View this video to get details about the proposed statute. What is your opinion on this situation? Would you support the statute, make changes to the statute or not support it at all. Read and follow the directions at this link word doc. version and get ready to support your point of view

  Research Links:

• Types of Cancers - National Library of Medicine
• Ask NOAH about Cancer - New York Online Access to Health
• American Cancer Society - National Organization
• National Cancer Institute - National Organization
• Oncolink - University of Pennsylvania Cancer Center
• Cancer Guide - An information page by Steve Dunn
• The Dioxin Homepage - The EnviroLink Network
• CancerHelp UK - The University of Birmingham
• Lung Cancer - Lung Cancer Awareness Campaign

Cancer cannot be inherited, but the tendency to develop cancer is hereditary.

A taratogen is something that can cause malformations of an embryo or fetus.
A developing human embryo is most vulnerable to these substances in its earliest stages - even before a woman knows she is pregnant.