What IS cancer?

What is cancer and how does it form? The answer lies in the tiny building blocks that make up each one of us: cells.

Cells form tissues which form organs. If enough of the cells that make up a tissue in an organ become defective, then those defective cells become a tumor within the organ. Defective cells, or cancer cells, cannot carry out all of the functions that normal, healthy cells are supposed to carry out.

In other words, cancer cells do not play by the "rules" that all of the healthy cells follow - cancer cells are kind of like the "bad" kid in a school. A bad kid may convince some of the otherwise "good" kids in the school to join him in his bad behavior by making it look like he's having a lot of fun breaking windows and stealing notebooks from the supply closet. The bad kid is already a problem, but if he can convince enough of the other kids to join him in his antics, then the school may have an even bigger problem on its hands. If the group of bad kids grows large enough, the principal of the school has to call the police to help get the situation back under control.

Do you see how this relates to cancer? The one bad kid has successfully formed a group of bad kids - a tumor. The principal, or organ, calls the police for help - in this analogy, the call for help to the police are the symptoms that your body exhibits when it can't ward off the cancer cells any longer.

So, in our analogy, what is cancer? It's the gang of kids that can't be controlled by the school anymore.

Symptoms differ depending on the cancer, but a few of the more common ones are unexplainable weight loss, night sweats, itchy patches of skin, tiring easily, or the presence of enlarged lymph nodes.

Cancer cells are selfish and take away space in the organ that healthy cells used to occupy. And since cancer cells don't follow the rules, sometimes the tumors they form start growing out of the organ and spread to other organs within the body. Cancer cells may also release damaging hormones or chemicals into the body, which further the symptoms of cancer.

Not all defective cells become cancer cells. Going back to our school analogy, let's say that the bad kid's parents decide they've had enough of him and send him off to a boarding school; then the bad kid is no longer a threat to the school (your body) because he's gone. Similarly, sometimes defective cells are created but can't survive in your body - so they die before they are able to divide into two daughter cells (see what causes cancer for more on the division of a parent cell into daughter cells).

There are over 200 different cell types in your body, and each of these cell types "act" differently. Some of them divide faster into daughter cells than other types. Some of them respond to existing cancer treatments like chemotherapy and radiation and some of them don't. This is why there is a different treatment regime for each type of cancer - because the cells involved each type of cancer are different. This is also why there is not, and never will be, one "cure" for cancer - each type of cancer will require a different cure.

If you're looking for a more scientific explanation to What is cancer?, I recommend reading the information provided by the National Cancer Institute.

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