>>516569514 (OP)
Cancer is your own cells going rogue.
Every cell has a switch that kills itself. When it acts up, the body orders it to die and it flips that switch.
What if damage breaks the switch? What if damage prevents the cell from hearing the kill command?
Final correction mechanism is what allows us to survive our stay in the womb at all. Going from one fertilized cell to something like 12 trillion? Shit is going to go wrong.
Telomeres are repeating TG sequences that don't code for anything. They are sacrificial alleles that occupy both ends of the DNA strand in every cell that can undergo mitosis. Each time a cell divides, some telomere is torn off. When the telomeres get low (only 2 or 3 of the ~100 a fresh cell comes with are left) the cell no longer divides.
Cancer is the cell ignoring that. When the 'Hayflick Limit' is ignored, cells divide without reason and keep dividing until something critical fails.
There is no cure for cancer. At best, rogue cells can be destroyed in hope that new, undamaged cells take their place (remission).
People with moles, skin tags, birthmarks etc. are prone to rogue cells. They are the scars of rogue cell division that is halted at the Hayflick Limit. If you have a lot of such scars, you're probably destined to die of cancer.