Cancer Webquest – Flashcards

Self-sufficiency in growth signals Insensitivity to antigrowth signals Evading apoptosis (programmed cell death) Limitless replicative potential Sustained angiogenesis Tissue invasion and metastasis

For a normal cell to proliferate, it must receive a message telling it to do so. This helps keep the number of cells in the body in check. In contrast, cancer cells are independent operators. They can generate their own growth signals or respond to weak messages other cells ignore, freeing them from the growth constraints normal cells have.

Cells not only receive messages that tell them when to grow, they receive messages telling them to stay inactive, or as scientists say, quiescent. Cancer cells have learned to tune out these signals

In an adult human, more than one trillion cells are born every day. Normal cells are programmed to receive a message telling them when their time is up. This normal programmed cell death is often referred to as cell suicide, or apoptosis. Cancer cells have acquired the ability to evade this message.

Many human cells are born preordained to replicate about 60 or 70 times. Once they have arrived at this point, they stop growing, a process termed senescence. The telomeres, segments of DNA that are on the ends of a cell's chromosomes, keep track of these replications by getting smaller each time the cell doubles. When the telomeres get too short, a cell's ability to reproduce has come to an end and it dies. Cancer cells have acquired the ability to keep their telomeres from getting too short, which means they are able to replicate endlessly

Cells get the oxygen and nutrients they need to survive through blood vessels. The process by which blood vessels are formed, called angiogenesis, is tightly controlled by the body, and cells that are multiplying too quickly often die for lack of blood. Cancer cells can trigger the growth of blood vessels on their own, which allows the tumor not only to sustain itself but also to set up new colonies in other areas of the body.

If cancer stays in one place, doctors can frequently remove or treat it successfully. But as tumors grow, cancer cells give birth to descendants that are able to invade adjacent tissue and then travel to other parts of the body, or metastasize. Metastasis is the ultimate achievement of cancer cells; it is responsible for 90 percent of all human cancer deaths.

- multiply continually, forming a tumor or a mass. - invade into the surrounding tissue so that they start to destroy the function of a normal organ—this is called invasion. - pread to other parts of the body—a process called metastasis

Smoking and Tobacco Diet and Physical Activity Sun and Other Types of Radiation Viruses and Other Infections - these are called mutagens and carcinogens

Surgery Chemotherapy Radiation Therapy Targeted Therapy Immunotherapy

Removes tumors

A drug that attacks fast growing cells

Mutates the DNA of the cancer cells

Drugs that target specific genes and proteins related to cancer growth

Stimulates one's immune system to fight cancer