Source: NOVA: "Battle in the War on Cancer: Breast Cancer"
NARRATOR: How does a gene that causes cancer, known as an oncogene, work? Cells have genes that direct the formation of receptor molecules. Receptor molecules are like antennae sitting on the cell's surface. When they receive growth signals from the outside, they send a message to the cell nucleus that it's time to divide.
The oncogene causes a slight difference in the receptor molecule. Like an accelerator pedal stuck permanently to the floor, the receptor keeps signaling the cell to divide, whether or not the receptor is getting that message. The more oncogenes there are, the more receptors present that are sending a stream of signals for the cell to reproduce.
But how does cancer spread? How do cells escape into a person's blood stream and attach themselves in other parts of the body? First, the cells fasten to the membrane around the blood vessel. Then, they use a strong chemical to work their way through the tough membrane into the circulatory system, which carries them to new tissues and organs.
Scientists understand the molecules that accompany each of these steps, and are trying to develop drugs to stop them. Other therapies are aimed at shutting down the receptor molecules to stop the cancer from growing.
Academic standards correlations on Teachers' Domain use the Achievement Standards Network (ASN) database of state and national standards, provided to NSDL projects courtesy of JES & Co.
We assign reference terms to each statement within a standards document and to each media resource, and correlations are based upon matches of these terms for a given grade band. If a particular standards document of interest to you is not displayed yet, it most likely has not yet been processed by ASN or by Teachers' Domain. We will be adding social studies and arts correlations over the coming year, and also will be increasing the specificity of alignment.