Cancer medically known as malignant neoplasm is a genetic condition caused by changes to genes that control the way the cell functions, especially the way the cells grow and divide. It can either be inherited or arise from certain environmental exposures or genetic changes that occur because of errors as cells divide. Cells have different mechanisms to restrict cell division, repair DNA damage and prevent the development of cancer. Multiple mechanisms must fail before a critical mass is reached and cells become cancerous. Different types of cancer involve different types of mutations, and, each individual tumor has a unique set of genetic alterations. Genetic changes occur in three main types of genes: Proto-oncogens, tumor suppressor genes and DNA repair genes that can contribute to cancer.
The uncontrolled proliferation of cells are usually linked to a series of changes in the activity of two types of cell cycle regulators: Positive regulators that may be over activated (become oncogenic) and negative regulators, also called tumor suppressors which might get inactivated. For example an important tumor suppressors is tumor protein p53 that control cell cycle progression, apoptosis, cellular sequence, DNA repair and genome maintenance. P53 primarily acts at the G1 where it blocks cell cycle progression in response to damaged DNA or other unfavorable condition.
Chemotherapy agents target different parts of the cell cycle and have different mechanisms of action and target different parts. The cycle repeats itself with various checkpoints that makes sure that there are no abnormalities in the cell before it progresses to each phase. These checkpoints include the G1 checkpoint which checks the damaged DNA, the G2 checkpoint that checks the un-replicated or damaged DNA and the M phase checkpoint that looks for chromosome misalignment, they look at whether their abnormalities damaged the DNA.
Cancer
medically
known as malignant neoplasm is a
genetic
condition caused by
changes
to genes that control the way the
cell
functions,
especially
the way the
cells
grow and divide. It can either
be inherited
or arise from certain environmental exposures or
genetic
changes
that occur
because
of errors as
cells
divide.
Cells
have
different
mechanisms to restrict
cell
division, repair DNA damage and
prevent
the development of cancer. Multiple mechanisms
must
fail
before
a critical mass
is reached
and
cells
become cancerous.
Different
types
of cancer involve
different
types
of mutations, and, each individual
tumor
has a unique set of
genetic
alterations.
Genetic
changes
occur in three main
types
of genes:
Proto-oncogens
,
tumor
suppressor genes and DNA repair genes that can contribute to cancer.
The uncontrolled proliferation of
cells
are
usually
linked to a series of
changes
in the activity of two
types
of
cell
cycle
regulators:
Positive
regulators that may be over activated (become
oncogenic
) and
negative
regulators,
also
called
tumor
suppressors which might
get
inactivated.
For example
an
important
tumor
suppressors is
tumor
protein p53 that control
cell
cycle
progression, apoptosis, cellular sequence, DNA repair and genome maintenance. P53
primarily
acts at the G1 where it blocks
cell
cycle
progression in response to
damaged
DNA or other unfavorable condition.
Chemotherapy agents target
different
parts of the
cell
cycle
and have
different
mechanisms of action and target
different
parts. The
cycle
repeats itself with various checkpoints that
makes
sure that there are no abnormalities in the
cell
before
it progresses to each phase. These checkpoints include the G1 checkpoint which
checks
the
damaged
DNA, the G2 checkpoint that
checks
the
un-replicated
or
damaged
DNA and the M phase checkpoint that looks for chromosome misalignment, they look at whether their abnormalities
damaged
the DNA.