Your body is made up of trillions of tiny cells that all work and cooperate together to create you.  Every day, billions or trillions of cells die and and a similar number are freshly created through the division of cells.  A single cell can divide into two cells by making an extra copy of all its DNA and then splitting into two cells.  That is how new cells are created, by the division of one cell into two cells.  Cells are very tiny.  A chunk of tissue the size of a sugar cube will contain about one billion (1,000,000,000) cells.

All your cells work in harmony within its particular organ and body.  Hormones and other signals tell the cell what to do, what substances it should make, whether it should divide, or whether it should die.

Cancer occurs when one of your normal cells goes rogue.  It starts ignoring the signals for when it should divide or when it should die, and it starts dividing under its own control.   It is a little like certain politicians who are no longer working for the good of their political party but are seeking their own agenda.  Unfortunately, when a bad cell divides, every new cell it creates will also contain the rogue instructions that make it too want to divide willy-nilly.   Soon there is an army of rogue cells, and this is when it is called cancer.  Cancer has no intelligence and no agenda.  It is not trying to hurt you.  The cells are simply no longer responding to control from the body and they are dividing aimlessly.  In addition, these cancer cells may no longer respect the boundaries of where they are supposed to live in the body, so they might end up spreading to tissues outside the prostate gland or even in lymph nodes or bones.

All cells contain DNA, which is like the computer programming for the cell, basically the instructions that tell it what proteins to make and how to play nicely within its particular organ.  If the DNA becomes damaged, then the programming becomes incorrect, and this is why a cell stops behaving properly.  This abnormal DNA then gets passed on to all the daughter cancer cells.  There are many harmful chemicals that can cause damage to DNA and these are some of the causes of cancer.

Cancer tends to get worse.  When it first starts, the cells are usually dividing just a little more often than they should, but the body can still keep it under control.  This is the pre-cancer phase  Gradually over months and years additional DNA damage creeps into some of the daughter cells, and the cells gradually become less and less responsive to the body’s signals.  Eventually an untreated cancer will spread, i.e. metastasize.