The which contains several thousand of repeating

The
development of cancer is a multi-step process, each step reflecting a genetic
change that alters a normal cell into a malignant cell. 4 The changes are
summarised in six essential alterations to cell physiology that collectively
order malignant growth. 4

Self-sufficiency in growth signals
Normal cells require growth cells to proliferate. Cancer calls gain the ability
to produce their own growth signals and synthesise growth factors to which they
can respond to. This results in cells operating as a separate entity in
comparison to functioning as part of a larger organism. 4

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

Insensitivity to inhibitory signals
Cells decide whether to proliferate or not, they make this decision by
monitoring their external environment. Many anti-proliferative signals function
via the retinoblastoma (Rb) protein, therefore once this is disrupted, control of the cell cycle is
lost resulting in cells proliferating. The Rb protein is a tumour suppressor. 4
5

Evasion of apoptosis
Apoptosis is programmed cell death which exists in almost every cell in the
human body. Mainly all cancers have the characteristic to resist apoptosis. A
way in which apoptosis may be avoided is the loss or mutation of the gene P53
which codes for a protein that regulates the cell cycle and functions as a
tumour suppressor. 4

Limitless replicative potential
It was suggested that normal cells can only undergo approximately 60-70
replications, once the maximum number of replications have been reached the
cell will stop growing and eventually die. However, cancer cells have developed
the capability of boundlessly replicating due to an enzyme known as telomerase.
There is a region known as the telomere at the end of every chromosome which
contains several thousand of repeating base pairs. During each normal cell
replication, the telomeres shorten until they are no longer able to protect the
chromosomal DBA, thus resulting in cell death. When telomerase is up-regulated
the telomeres will be maintained above a critical length thus making the cell
immortal. 4

Tissue invasion and metastasis
Metastasis is the spread of cancer to different regions of the body from where
it started. 6 The cytoskeleton of the cell is rearranged, which allows the
cell to attach to other cells and move over or around them. When there is
something is in the way of the cancer cells, the cancer cells secrete enzymes
in order to break the blockage down. These enzymes include matrix
metalloproteins (MMP) which are known to act as ‘molecular scissors’, which cut
through proteins that may hinder the passage of cancer cells. Once the blockage
is surpassed, the cells can continue into the bloodstream and circulate
throughout the body until the cells have found a suitable site to settle and
proliferate. 4

x

Hi!
I'm Dana!

Would you like to get a custom essay? How about receiving a customized one?

Check it out