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The central role of DNA damage and epigenetic defects in DNA repair genes in carcinogenesis. DNA damage is considered to be the primary cause of cancer. [17] More than 60,000 new naturally-occurring instances of DNA damage arise, on average, per human cell, per day, due to endogenous cellular processes (see article DNA damage (naturally occurring)).
Scientist Otto Warburg, whose research activities led to the formulation of the Warburg hypothesis for explaining the root cause of cancer.. The Warburg hypothesis (/ ˈ v ɑːr b ʊər ɡ /), sometimes known as the Warburg theory of cancer, postulates that the driver of carcinogenesis (cancer formation) is insufficient cellular respiration caused by insult (damage) to mitochondria. [1]
A proto-oncogene is a normal gene that could become an oncogene due to mutations or increased expression. Proto-oncogenes code for proteins that help to regulate the cell growth and differentiation. Proto-oncogenes are often involved in signal transduction and execution of mitogenic signals, usually through their protein products.
The basic cause of sporadic (non-familial) cancers is DNA damage and genomic instability. [1] [2] A minority of cancers are due to inherited genetic mutations. [3] Most cancers are related to environmental, lifestyle, or behavioral exposures. [4] Cancer is generally not contagious in humans, though it can be caused by oncoviruses and cancer ...
These mutations are caused by carcinogens through external and internal factors. Carcinogens are chemical or physical agents that cause DNA damage, which may later develop into cancer. They can initiate mutagenesis in DNA by interfering with the replication process. [3] These interactions typically cause chemical adducts to form in the cell.
It was later found that carcinogenesis (the development of cancer) depended both on the mutation of proto-oncogenes (genes that stimulate cell proliferation) and on the inactivation of tumor suppressor genes, that keep proliferation in check. Knudson's hypothesis refers specifically, however, to the heterozygosity of tumor suppressor genes.
Carcinogens can be classified as genotoxic or nongenotoxic. Genotoxins cause irreversible genetic damage or mutations by binding to DNA. Genotoxins include chemical agents like N-nitroso-N-methylurea (NMU) or non-chemical agents such as ultraviolet light and ionizing radiation. Certain viruses can also act as carcinogens by interacting with DNA.
Cells of the body don't normally have the ability to divide indefinitely. They have a limited number of divisions before the cells become unable to divide , or die (crisis). The cause of these barriers is primarily due to the DNA at the end of chromosomes, known as telomeres. Telomeric DNA shortens with every cell division, until it becomes so ...