Hey @james (and cheers Dustin and James). Basically, cancer is just uncontrolled growth of cells in a particular organ. We have many genes that regulate how cells grow/divide and when to stop. What happens in cancer is that these genes become “faulty” and that when cell division/growth is supposed to stop, in cancer it keeps growing/dividing to make new cells. Also, there are genes that regulate programmed cell death (known as apoptosis). Essentially, this happens when there are enough cells to get the job done. So the genes that are usually switched off (and therefore can regulate the cell growth/death) are switched on (therefore not being able to stop growth) and the tumour grows and grows……