Jun 29, 2020
Where does a cancer come from?
Cancer begins with one cell.
A normal cell has cell membrane, a cytoplasm with lots of working parts within it, and a central nucleus. The nucleus contains the instructions, the DNA, that tells the cell exactly what it needs to do. A cell has a specific purpose, become a prostate cell for instance or skin or a brain.
Our DNA is incredible. Using the nucleobases adenine, cytosine, guanine, and thymine base pair nucleosides of adenine-thymine and cytosine-guanine can be stacked, one on top of another, into chromosomes, long chains of coiled double helix code that is read by the cell as the ultimate instruction manual. The instructions contained within a single cell is more complex than any how-to book you have ever read. The full set of instructions is so long that it would take more than 3,000 books to print all of the instructions assuming that each book would have 1,000 pages. If you could take the DNA out of a single cell and stretch it into a line, it would be more than six feet long.
To grow a prostate or skin or a brain, a cell must replicate itself over and over. Cell division and replication happens in a process called mitosis. During mitosis a cell’s DNA needs to be replicated exactly to form a duplicate cell. One cell into two, two into four, four into eight and so on. The cells must then all work together to create a prostate or skin or a brain.
Here is the origin of a potential cancerous cell.
Any loss of integrity to the DNA causes the entire cell to be dysfunctional, either completely or partially. The new imperfect DNA contains an imperfect set of instructions.
Most often the mutation will be fatal to the cell. That cell dies. No big deal.
nfrequently, a mutation will form a non-lethal cell change and the abnormal cell will not follow the normal growth pattern.
A cell that continues to grow and does not get the appropriate instructions for growth eventually becomes a problem. It continues to grow and divide, replicating its own DNA. One to two, two to four, four to eight and so on until there is a mass of cells, a tumor, that is not following normal instructions.
An individual cancer cell, depending on the type of mutation within it, will have its own unique growth pattern. When we look at a cancer cell under the microscope we can predict how aggressively it will behave by how undifferentiated the cell is. Each cancer has its own grading system.
Cancers start within one organ. Prostate cancer starts in the prostate cells, breast cancer from the breast, skin cancer in the skin, and colon cancer in the colon.
Then it spreads to other parts of the body. Cancers metastasize.
Cancers spread in one of two ways They grow 1. by local spread and 2. By distant spread, travelling hematogenously (through the blood) or lymphatically (through the lymph system). A metastatic cancer is one that has spread to other organs through either local invasion or through the blood or lymph.
A cancers stage is often classified in a staging system we call TNM. T, tumor. What is the tumor doing? Is it confined to the organ or has it advanced locally? N, lymph nodes. Are there any swollen lymph nodes that would indicate that a cancer has spread to the lymph system. M, metastases. Is there evidence of cancer in other parts of the body? TNM each are given a number. An overall stage is often a number as well and is a consolidation of the TNM classification.
How does a cancer do this, grow such that the body doesn’t fight it off?
Your body often does not recognize the cancerous cell as abnormal, or just downright turns its head away and ignores it until its too late.
Our immune system detects and kills bad stuff through a complex interplay of B cells, T cell, Natural killer cells, humoral immunity and cellular immunity working together to detect the abnormal and destroy it.
The body has the ability to detect self from non-self. Our bodies tissues have normal markers on the cell surface that tell our immune system, “hey, we are one of the good guys.”
Cancer cells evade the normal immune signals that would otherwise find and destroy it. They confuse it, or exhaust it, or disrupt it.
And the cancer cells grow, spread and destroy.
We must get rid of it to survive.