7th Grade Science Notes
April 18, 2007
Cancer
§ Cancer is the general name for a disease in which cells grow and divide uncontrollably, damaging the tissue around them. Cancers can arise in any part of the body.
§ Cancers are caused by one or more mutations to the DNA of a cell, disrupting the cell cycle and causing the cell to divide too fast and too often. Sometimes abnormal proteins are also made by the cancer cell.
§ A tumor is a large number of rapidly dividing cells. Some tumors are malignant (cancerous) and some are benign (non-cancerous).
§ A malignant tumor is one where the cancer cells can break away and travel through the lymph or circulatory system to form new tumors.
§ A benign tumor is a non-cancerous growth where the cells do not break away to form new tumors.
Causes of cancer:
§ There are over 100 known types of cancer and many have unknown causes. However, cancer is NOT contagious, though a few are linked to a person’s genes.
§ Damage to a cell’s DNA can be caused by exposure to chemicals, radiation, or certain viruses.
§ An example of chemical exposure is tobacco use which causes lung cancer.
§ An example of radiation exposure is the ultraviolet light from the sun which causes skin cancer.
§ An example of a virus that causes cancer is the HPV virus that is linked to cervical cancer.
Cancer treatment:
§ In all cancer treatments, the goal is to kill the cancer cells without damaging the healthy cells in a person’s body. This is very hard to do.
§ Surgery to remove the tumor is the first step of cancer treatment.
§ Chemotherapy involves the use of drugs to kill the cancer cells, though the drugs often affect a person’s healthy cells too.
§ Radiation therapy is used to kill any tumor cells that are too small or too spread out to be removed surgically.
Cancer prevention:
§ By minimizing your exposure to chemicals (DON”T SMOKE) and radiation (USE SUNSCREEN), you can reduce your risk for those types of cancer.
§ A healthy diet and lifestyle is associated with a reduced risk for cancer.