Cells with certain alterations in tumor suppressor genes may divide in an uncontrolled manner.ĭNA repair genes are involved in fixing damaged DNA. Tumor suppressor genes are also involved in controlling cell growth and division. However, when these genes are altered in certain ways or are more active than normal, they may become cancer-causing genes (or oncogenes), allowing cells to grow and survive when they should not. Proto-oncogenes are involved in normal cell growth and division. These changes are sometimes called “drivers” of cancer. The genetic changes that contribute to cancer tend to affect three main types of genes- proto-oncogenes, tumor suppressor genes, and DNA repair genes. How Does Cancer Develop?Ĭancer cells can break away from the original tumor and travel through the blood or lymph system to distant locations in the body, where they exit the vessels to form additional tumors. For example, some cancer therapies prevent blood vessels from growing toward tumors, essentially starving the tumor of needed nutrients. Researchers have taken advantage of this fact, developing therapies that target the abnormal features of cancer cells. Many times, cancer cells rely so heavily on these abnormal behaviors that they can’t survive without them.

This lets cancer cells grow more quickly. In addition, some cancer cells make energy from nutrients in a different way than most normal cells.

rely on different kinds of nutrients than normal cells.

Some cancer cells have double the normal number of chromosomes.

accumulate multiple changes in their chromosomes, such as duplications and deletions of chromosome parts.

For instance, some cancer cells convince immune cells to protect the tumor instead of attacking it.

trick the immune system into helping cancer cells stay alive and grow.

The immune system normally eliminates damaged or abnormal cells. These blood vessels supply tumors with oxygen and nutrients and remove waste products from tumors.

tell blood vessels to grow toward tumors.

Normal cells stop growing when they encounter other cells, and most normal cells do not move around the body.

invade into nearby areas and spread to other areas of the body.

ignore signals that normally tell cells to stop dividing or to die (a process known as programmed cell death, or apoptosis).

Normal cells only grow when they receive such signals.

grow in the absence of signals telling them to grow.Have questions? Connect with a Cancer Information Specialist for answers.Ĭancer cells differ from normal cells in many ways. Differences between Cancer Cells and Normal Cells Some can cause serious symptoms or be life threatening, such as benign tumors in the brain. Benign tumors can sometimes be quite large, however. When removed, benign tumors usually don’t grow back, whereas cancerous tumors sometimes do. Many cancers form solid tumors, but cancers of the blood, such as leukemias, generally do not.īenign tumors do not spread into, or invade, nearby tissues. Cancerous tumors may also be called malignant tumors. Tumors can be cancerous or not cancerous ( benign).Ĭancerous tumors spread into, or invade, nearby tissues and can travel to distant places in the body to form new tumors (a process called metastasis). These cells may form tumors, which are lumps of tissue. Sometimes this orderly process breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t. When cells grow old or become damaged, they die, and new cells take their place. Normally, human cells grow and multiply (through a process called cell division) to form new cells as the body needs them. of Pittsburgh Cancer Institute The Definition of CancerĬancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body.Ĭancer can start almost anywhere in the human body, which is made up of trillions of cells. Credit: National Cancer Institute / Univ.

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