Are all the different cancers really that different or is it all just cancer and we just specify where it formed?
In: Biology
With the caveat that its been nearly 20 years since I’ve worked as a cancer researcher, this is what I learned:
YES all cancers are different. But they follow patterns of behavior that let us have a good guess as to how aggressive they will be and what drugs will work against them. And knowing what kind of cell the cancer started out as can give us good clues.
Every cell in your body has a job to do and it has a special shape to let it do its job and special proteins that it makes to let itself do its job. Its important that every cell stay in place and do Only the one job it is supposed to do. Nerves are nerve shaped and send electric signals, pancreas cells are round and secrete insulin, etc. And the cells all constantly send chemical signals to each other that say “stay alive, stay in place, stay the right shape and size, only do your own job, and DO NOT GROW AND DIVIDE to make more cells like you unless directed. Cells that obey these commands are ‘differentiated’.
Some cells are ‘allowed’ to divide: like the cells in a growing embryo, or the cells in your bone marrow that make fresh blood for your body, or the cells near a wound that is in the process of healing.
If you take a cell from one organ and stick it into another, it will fail to receive the correct “stay alive” signal and it will commit suicide (apotosis). Also, there are immune cells wandering the body, looking for and executing rogue ‘pre-cancerous’ cells. And there are other failsafes too. Your whole body is constantly policing every cell, to look for dangerous cells that are getting out of line.
But if these fail-safes don’t work, and an individual cell starts to lose its special shape, to divide out of control and make millions of new cells like itself, that is cancer.
Cancer starts growing wherever the original mutant cell was. The lump of millions of overgrown mutant cells is called a tumor.
The millions of decendants of the original cancer cell often develop new mutations that allow them to leave the original tumor and slip into the bloodstream and migrate to new parts of the body to make new tumors.
The way a cell turns cancerous is that it has many random bits of damage its DNA that happen to ruin its ability to recognize and respond to the chemical signals that tell it to behave. There are multiple layers of anti-cancer back up systems for each type of cell, so it takes about six or more different mutations to turn a healthy cell into cancer.
A pre-cancerous cell divides and grows and makes decendants. Some of those cells gain new mutations that make them more dangerous. And some of their offspring have even more dangerous mutations.
Each mutation lets the cell gain a new bad behavior until it has enough bad behaviors to grow into a large mass. Some of these bad behaviors: grow too fast, start ordering nearby blood vessels to give more blood to me, learn how to move from one place to another in the body, learn how to hide from cells that detect pre-cancerous cells, learn how to ignore when other cells tell me that I’m growing in the wrong place.
Each type of cell in the body has different types of signals and controls that keep its cells from becoming cancer, so the path to turning into cancer is different for every type of cell.
Every cancer is as unique as the random mutations that created it, but cancer cells still have some of the traits of whatever original kind of cell they started out as. We have found certain medicines that work well for cancers that started out in certain regions of the body. There are special drugs for lung cancer and breast cancer and bone marrow cancer.
We can now do tests that give us a lot of very good information on what type of cell the cancer started as and even what types of mutations it has. This tells what bad behaviors it is likely to have and what drugs will thwart it.
Latest Answers