Strings of four deoxyribonucleic acid (DNA) units called bases comprise the genetic material of a cell.
DNA bases are organized into genes. The order, or sequence, of the bases
provides the code used by the cell to produce the various proteins it needs to function.
The entirety of a person’s DNA is called the genome. Almost every cell in the body contains
a copy of the genome. The genome is packaged together with proteins known as histones
into structures called chromosomes.
Special chemical marks, called epigenetic marks, on the DNA and histones together
determine whether a gene is accessible for reading. The sum of these chemical marks
across the entire genome is called the epigenome.
The accessible genes within each cell are read to
produce the proteins that ultimately define the
cell and tissue function in which the cell resides.
GENETIC AND EPIGENETIC CONTROL OF CELL FUNCTION
Adapted from ( 1)
Single base changes
• Some mutations can lead to the generation of altered versions of normal proteins,
and these may cause cancer to develop.
• Deletion or insertion of a single base can result in new proteins or loss of protein function, which can lead to cancer.
Extra copies of genes (gene amplification)
Higher quantities of certain proteins can result in enhanced
cell survival and growth, leading to cancer.
Loss of DNA can result in loss of genes necessary to stop or control the growth of cancer.
Exchange of DNA across different parts of the genome can lead to
entirely new proteins that can drive the development of cancer.
Mutations that alter the epigenome
Several proteins read, write, or erase the epigenetic marks on DNA or the histones around
which it is packaged. Mutations in the genes that produce these proteins can lead to cancer.
Adapted from ( 1)
The following are some of the types of genetic mutation known to lead to cancer.
Of note, genetic mutations do not always result in cancer. ATCG X