What is a Tumor?

What is a tumor? A tumor is a group of cells in the body that have begun growing uncontrollably and form a mass.

Normally, cells in our body are very tightly regulated and controlled, only dividing and producing more cells when absolutely necessary. For example, skin cells normally divide at some rate to replace dead skin cells which are sloughed off our skin surface constantly. Some cells, like skin cells and bone marrow cells (which produce our blood cells), divide and grow relatively rapidly, while others rarely if ever divide. But however fast or slow normal cells in our body grow, their growth and division is very tightly regulated by our genetics, the "blueprint" for our bodily functions. Cells are under many restraints that limit the amount and speed at which they can divide and produce more cells.

So what is a tumor? How is it different from normal cells? Well, during a lifetime, cells can become damaged by various factors. If cells have damage to their DNA, their genetic material, it can impact how they function. These areas of damage to DNA, called mutations, can affect the way a cell divides. If just the right mutations affect a given cell, that cell may be able to break free of its normal restrictions and begin to divide when it is not suppossed to divide. These cells are then considered a tumor.

"Tumor" literally means a swelling or mass, because as most tumors grow and the cells continue to divide, they generally form an enlarging lump or mass. These masses can cause problems if they begin to impact the normal tissues around it, eventually leading to symptoms, which is why a tumor can be a problem.

What is a tumor and how is it different from cancer? In fact, cancer is a type of tumor. Tumors can vary considerably in many ways. First of all, tumors can potentially arise from just about every tissue type and organ in the body, the skin, the lungs, the brain, the intestines, the liver, etc. But that is not the only way that tumors vary from one another. They also vary on a spectrum in terms of their aggressiveness and invasiveness in the body. Tumors that lie on the less aggressive and invasive end of the spectrum are termed benign tumors while those on the more aggressive and invasive end of the spectrum are called malignant tumors. Cancer is a malignant tumor.