What Is cancer, exactly?

(I'm still not going to captilize the c in cancer)
cancer cells, in layman's terms, are *abnormal cells that grow uncontrolably within one's body. Most of the time, it is normal cells that have turned bad and attack the host instead of protecting the host.
The beginning......We were all born with a system called the IMMUNE SYSTEM that is broken down into many immune systems in every part of the body. Each system has a built-in monitor or protective mechanism that keeps that system functioning up to par. If we have a problem somewhere, it is because this immune system for that particular system failed us and permitted the enemy to enter. Examples of the various culprits that put a strain on our immune system are viruses, parasites, bacteria etc...you get the idea.
When these abnormal cells start growing and "bump" into each other, they multiply and continue to grow, even if they are running out of room in that particular part of the body, then lumps or tumors are formed. When cells get too numerous for this particular "home",(jump the "fence" into another part of the "neighborhood") they detach themselves from the tumor and move via the bloodstream to other parts of the body where they begin to form further tumors. This process is called metastasis.

When a cancer spreads from its original site to another area of the body, it is termed metastatic cancer. Metastatic cancer cells invade lymph vessels and blood vessels near a tumor and migrate to other parts of the body. The cells in a metastatic tumor resemble those in the primary tumor and are usualy named the same as the primary. For example, breast cancer that spreads to the lungs and forms a metastatic tumor is metastatic breast cancer, not lung cancer.

Some Key Points about Metastatic cancer
~Some people with metastatic tumors do not have symptoms. Their metastases are found by scans or other tests
~The most common sites of cancer metastasis are the lungs, bones, and liver.
~Treatment for metastatic cancer usually depends on the type of cancer and the size, location, and number of metastatic tumors.

Stages of cancer
Staging describes the severity of a person’s cancer based on the extent of the original (primary) tumor and whether or not cancer has spread in the body.

Stage I, Stage II, and Stage III
Higher numbers indicate more extensive disease: Larger tumor size and/or spread of the cancer beyond the organ in which it first developed to nearby lymph nodes and/or organs adjacent to the location of the primary tumor.
Stage IV
The cancer has spread to another organ(s).

*abnormal cells: abnormal number of chromosomes in some cells, where certain ones have incorporated a number of extra chromosomes while others wind up with too few.