What causes cancer?
There
is no one single cause for cancer.
Scientists
believe that it's the interaction of the many factors along that produce cancer.
The
factors concerned could also be genetic, environmental, or constitutional
characteristics of the individual.
Diagnosis,
treatment, and prognosis for childhood cancers square measure completely
different than for adult cancers.
The
main differences are the survival rate and the cause of cancer.
The
overall five-year survival rate for childhood cancer is concerning eightieth,
while in adult cancers the survival rate is 68%.
This
distinction is assumed to be as a result of childhood willcer is a lot of awake
to medical care and a baby can tolerate a a lot of aggressive medical care.
Childhood
cancers typically occur or begin within the stem cells, which are simple cells
capable of producing other types of specialized cells that the body needs.
A
discontinuous (occurs by chance) cell modification or mutation is typically
what causes childhood cancer.
In
adults, the kind of cell that becomes cancerous is typically AN vegetative cell.
Epithelial
cells line the body cavity and canopy the body surface.
Cancer
happens from environmental exposures to those cells over time.
Adult
cancers square measure generally named as none heritable for this reason.
The
discovery of pure forms of genes that contribute to cancer has been an
especially vital development for cancer analysis.
Over
ninetieth of cancers square measure discovered to own some sort of genetic
alteration.
Some
of these alterations square measure transmissible, whereas others square
measure discontinuous, which means they occur by chance or occur from environmental
exposures (usually over many years).
Types
of cancer genes
There
square measure 3 main forms of genes that may have an effect on cell growth and
square measure altered (mutated) in sure forms of cancers, including the
following:
•Oncogenes:
These genes regulate the normal growth of cells.
Scientists
unremarkably describe oncogenes as the same as cancer "switch" that
the majority of individuals have in their bodies.
What
"flips the switch" to form these oncogenes suddenly become unable to
regulate the conventional growth of cells and permitting abnormal cancer cells
to start to grow, is unknown.
•Tumour
suppressor genes: These genes are able to recognize abnormal growth and
reproduction of damaged cells or cancer cells, and can interrupt their
reproduction until the defect is corrected.
If
the growth suppressor genes square measure mutated, however, and they do not
function properly, tumour growth may occur.
•Mismatch-repair
genes: These genes help recognize errors when DNA is copied to make a new cell.
If
the deoxyribonucleic acid doesn't "match" utterly, these genes repair
the couple and proper the error.
If
these genes don't seem to be operating properly, however, errors in
deoxyribonucleic acid are often transmitted to new cells, causing them to be
damaged.
Usually
the number of cells in any of our body tissues are tightly controlled so that
new cells are made for normal growth and development, as well as to replace
dying cells.
Ultimately,
cancer may be a loss of this balance thanks to genetic alterations that
"tip the balance" in favour of excessive cell growth.
Cancer
is caused by accumulated damage to genes
Such
changes could also be thanks to the likelihood or to exposure to cancer
inflicting substance.
The
substances that cause cancer are called carcinogens.
A
matter could also be a chemical substance, such as certain molecules in tobacco
smoke.
The
explanation for cancer could also be environmental agents, viral or genetic
factors.
We
should bear in mind, though, that in the majority of cancer cases, we cannot
attribute the disease to a single cause.
We
can roughly divide cancer risk factors into the subsequent groups:
1.biological
or internal factors, such as age, gender inherited genetic defects and skin type
2.environmental
exposure, for instance to radon and UV radiation, and fine particulate matter
3.occupational
risk factors, including carcinogens such as many chemicals, radioactive
materials and asbestos
4.lifestyle-related
factors.
Lifestyle-related
factors that cause cancer include:
•tobacco
•alcohol
•UV
radiation in sunlight
•some
food-related factors, such as nitrites and polyaromatic hydrocarbons generated
by barbecuing food).
Lifestyles
can prevent cancer
Cancer
inflicting factors associated with work and living environments include:
•asbestos
fibres
•tar
and pitch
•polynuclear
hydrocarbons (e.g. benzopyrene)
•Some
metal compounds
•Some
plastic chemicals (e.g. Vinyl chloride)
Bacteria
and viruses can cause cancer:
•Helicobacter
pylori (H. pylori, which causes gastritis)
•HBV,
HCV (hepatitis viruses that cause hepatitis)
•HPV
(human papillomavirus, papillomavirus, which causes changes eg. Cervical cells)
•EBV
(Epstein-Barr virus, the herpes virus that causes inflammation of the throat
lymphoid)
Radiation
can cause cancer:
•ionising
radiation (e.g. X-ray radiation, soil radon)
•non-ionised
radiation (the sun’s ultraviolet radiation)
Some
drugs may increase the risk of cancer:
•certain
antineoplastic agents
•certain
hormones
•medicines
that cause immune deficiency
In
5 – 10 per cent of breast cancer genetic predisposition plays an important role
in the emergence of the disease