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CANCER
What Is Cancer?
Cancer happens when people have enormous amount of cancer cell.
Cancer cell donot responds to normal mechanism that controls cell
cycle and cell development. They will
divide rapidly to form mass of a tumour, which they divide in
enormous rate. The tumour
may split up, releasing small clumps of cells into the blood or
lymph systems, where they will
circulate and then lodge into different areas of body. They
continue their cell division at other
places to form different tumours. This splitting is called
metastasis. A tumour that invades
surrounding tissue and metastasises is known as a malignant
tumour.
Not only do cancer cells divide more rapidly, they also can live
longer. The enlarging
tumour completely disrupts normal tissues, they also kill the
organisms.
What Causes Cancer?
According to the research, it has been found that not all types
of cancer come from genes. In
general, cancer can possibly comes from genetic or environmental
factor.
a) Environmental Factor
People always consider cancer as coming from their genes. ome of
the diseases do
comes from genetic factor but some of them do results from
environmental factor. According
to a cancer researcher, !r "el #reaves, author of $volutionary
%egacy has drawn a stronger
conclusion than the twins study. &e made a research about
factors of cancer. A pair of twin
was selected. In an article from C'C News, #reave said that
environmental factor was ()*
while genetic factor only +)*. This is because due to the
pollution of air, natural substances
in food and changes in reproductive habits and our normal
hormone can also causes cancer.
People can get can cancer by smoking habit. It is a leading
cause. Cigarette smoke
contains more than ,-)) individual chemicals, and more than )
are carcinogenic /cancer
causing0. Consuming fatty foods and alcoholic beverages can also
lead to cancer. kin
e1posure to ultraviolet rays can cause melanoma, a skin cancer.
e1ual behaviour that helps
spread se1ually transmitted diseases can brings to cervical
cancer in woman. Cancer also can
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caused from chemicals which been ingested by our body through
pollinated drinks, air and
food.
b) Genetic Factors
$gg and sperm are 2germ cells3. If there are alteration or
mutation on the genes, it is
called as 2germ4line mutation3. 5hen a germline mutation
inherited, it is present in all
body cells. 6n the other hand, mutation that we are not born
with but that occur by
chances over time in the cell of the body are said to be
2ac7uired3. Ac7uired mutation are
always involved in causing cancer. #ermline mutation are
involved in a small
percentages of cases.
The formation of tumour is the one that cause cancer. If there
are alteration and mutation
of the !NA of genes that involved in cell division, cancer will
happen. The e1ample of
gene are oncogenes, tumour suppressor genes and !NA repair
genes.
6ncogenes are altered form of genes of proto4oncogenes.
Proto4oncogenes are
responsible to control cell division. 5hen it became oncogene,
it promote tumour
growth.
Tumour suppressor gene can control process of cell growth and
cell death
/apoptosis0. 5hen it is mutated, the brake of cell division is
removed and it can
led to tumor mutation.
!NA repair genes are the genes that correct the
naturally4occuring spelling error
in the !NA, which happens during copying of !NA code. 5hen
mutation
happens, the mistakes of the !NA code remains. If this happens
to cell which aidin cell division, tumour can be formed.
