Answer:
The body is made up of approximately 37.2 trillion human cells – so you can truly appreciate how many that is, here is the number written out in full, 37,200,000,000,000 – that’s a lot of cells.
These ‘normal’ cells act as the body’s basic building blocks and possess specific characteristics that enable them to maintain correct functioning of tissues, organs, and organ systems. Normal cells:
control their growth using external signals, meaning they only grow and divide when required,
undergo programmed cell death (apoptosis) as part of normal development, to maintain tissue homeostasis, and in response to unrepairable damage,
‘stick together’ by maintaining selective adhesions that they progressively adjust which ensures they remain in their intended location,
differentiate into specialized cells with specific functions meaning they can adopt different physical characteristics despite having the same genome.
Cancer is a complex genetic disease that is caused by specific changes to the genes in one cell or group of cells. These changes disrupt normal cell function – specifically affecting how a cell grows and divides. In contrast to normal cells, cancer cells don't stop growing and dividing, this uncontrolled cell growth results in the formation of a tumor. Cancer cells have more genetic changes compared to normal cells, however not all changes cause cancer, they may be a result of it. The genetic changes that contribute to cancer usually affect three specific types of gene; proto-oncogenes, tumor suppressor genes, and DNA repair genes.
