人体的组织器官的状况永远都是处于于一个动态的过程,不停的有细胞死亡,又不停的产生新的细胞替代。正常的情况下,细胞一般不会无缘无故的分裂生长,得要有生长信号的刺激。细胞受生长因子的刺激生长,有点像咱们开车的时候踩油门,一脚油门踩下去,车子开始动起来了。正常情况下,车子开起来了,速度要有控制,还得有刹车的配合,该快的时候快,该慢下来避开障碍、要转弯的时候,就得踩刹车减速,不能横冲直闯的。 c
细胞里面还真的有这种对应的“刹车”装置,叫生长抑制因子。负责细胞生长的时候,适时的调整速度。使细胞生长得不快不慢,恰到好处。 m
英文:Rough Journey of
Cancer Cells Ultimately Growing into a Cancer Mass 6park.com
Part I: Internal Hurdles 6park.com
[This article is a layman’s version of the story for an important scientific issue. If the use of analogy somehow
contradicts with the latest theory, please give me your comments, we can
discuss it in detail. ] 6park.com
When we mention a cancer cell, it is indeed a terrible thing. This ‘guy’ is a real culprit, that contributes to one
of the annual lethal killers and tops the list of the few among them. This
time, however, I am taking the cancer cell’s stand, to present the rough
journey, in a view of an easy-to-understand language, as how the cancer cell
ultimately grows into a cancer mass. In the journey, the domestic or
internal challenges inside the cell and the foreign threats outside of the cell
come into play one after another to halter the processes. Here I would
strive for the topic written in a series. This is the first article [Part I:
Internal Hurdles], mainly from the cell's own genetic background or makeup, to
begin with my series of the topic. 6park.com
As we know, a bunch of the cancer cells are produced, and then cleared at approximately the same time, so that a
cohort of army, or majority of the so-called incipient cancer cells are in play
with the consequence of failure. However, being in parallel with the
threats, cancer cells with somewhat of a devilish mindset, are also learning
how to avoid being cleared of doom. 6park.com
Let’s start from the normal data from our human body. We, the human body, have approximately 10 trillion adult
cells. There are roughly 250-300 million cells per gram or cubic
centimeter of either liver tissue or renal one. Every cell accommodates haploid
genomic DNA bases (A, T, C, G) to as many as 3.2 billion more. It is said that
with the number of 3.2 billion letters, which would be more than enough to
draft equivalent to 1000 of different copies of the book of [the War and
Peace]. Here we will not marvel at the mystery of the organism in that
respect. 6park.com
To begin with our story, it is necessary to clarify some of the basic concepts. 6park.com
Cancer cell(s) could be a single cancer cell in existence, or just a few in numbers, in which its/their malignant
potency is/are not very high. They could also be the cells inside the
cancer mass, in which the degree of malignance reaches to the maximum
level. 6park.com
Cancer is a condition in which cancer cells grow to a certain degree. The body’s own defense mechanism can no
longer control and confine its malignant growth, which then is called
cancer. 6park.com
Ten trillion normal adult somatic cells are from a single fertilized egg. It is amazing how accurate the copies
of 10 trillion cells in a human body without apparent mistakes are made, so
that we, normal human beings, could lead a basic healthy life. On the
other hand, however, it is also impossible for all the 10 trillion cells to be
without any problem at all. Although there is very low probability for the
cells to become abnormal, here we would discuss it in this respect to proceed
to our topic. Let us assume that we have an abnormal rate of 1 in 100 million
cells. Although the abnormal rate is unimaginably low, there should be
approximately 100 thousand number of the problematic cells available. 6park.com
Under normal circumstances, there are a set of internal risk-proof devices in the cells. They can also be
called the self-destructive devices, ‘curses’, mechanisms, or an analogy to
that of the ‘lock-up’ or ‘shackles’ in figurative expression, to either destroy
or confine the problematic cells. Some cells deviate from normal path of
growth, or simply they are not going to be in use, they are doomed towards the
journey to hell. And some of them will be quarantined until they wear
away to die if they are not applicable to be completely destroyed right
away. So these few amount of abnormal cells are continuously produced,
killed or ‘imprisoned’ for their reasonable destiny, and thus, our normal body
could function as a whole temporarily in good standing. 6park.com
Our body tissues and organs are constantly in a dynamic process. Some cells will die and others more
regenerate. Under normal conditions, cells generally do not grow and divide
until the growth signal is applied. That means that the growth factor
engages on the cell to make the cell to grow. An analogy to understand
this is the way you drive your car. When one foots the gas pedal, the car
starts to move. Normally, it would be important to coordinate brake and gas
pedal for the speed control, in order to go fast and slow to avoid obstacles,
and, alternatively, when in need of a turn. It is true that inside the cell
there is also an equivalent of a brake device. It is called a growth
inhibitory factor, which is responsible for timely cell adjustment of speed to
make the cell to grow, neither fast nor slow, but just in perfect control. 6park.com
As it is known, all the activities of cells are controlled by the genes. If some cells genetically acquire some
altered changes or even mutation related to excessive growth signaling above
the normal level, then the equivalent of the ‘throttle is intensified’. In
addition, while the growth inhibitory factors are not timely matched up, as
that of brake device is thus not effective. Or alternatively, the growth
factor signaling is not escalating, and brake device is malfunctioning,
therefore the car goes all the way to accelerate. The cell acquired this kind
of capability(ies) or trait(s) is called the primary tumor or incipient cancer
cell. 6park.com
These are the first 2 genetic changes in the cell for its abnormality, although it is not necessary to
happen in parallel simultaneously. Here to put it in highlighted bold form as a
take-home message – GROWTH SIGHNALING increase/ GROWTH SUPPRESSOR decrease. 6park.com
At this point, no real threat could be clued, because these cells have not yet liberated from all the other applied
‘curses’ and ‘shackles’. If their strange behaviors reach a certain unbearable
level, they are doomed to be either escorted to the growth arrest, or to be
served for the countdown start of the self-destructive mechanism for
clearance. 6park.com
But ah, cancer cells are the ones of little devils. They do not care about the coordination with the body
tissue assigned activities. They are trying with every effort to gain in their
ground in competing the body with time and numbers. The ‘die-hard revolutionary
martyrs’, cancer cells die in a heroic course, but as long as they leave their
fire seed available or some newly recruits join their course. They continue to
make their great effort to work out a way or ways to take off the rest of the
‘curses’ and/or ‘shackles’ towards a liberation. 6park.com
APOPTOSIS is a mechanism that all normal cells possess, which is a noble and great trait for an individual
cell. This mechanism involves in a set of genes, which are orderly
controlled for the process. While the cells are damaged or somehow something
like that to critical extent, they find themselves either unable to fulfill
their normal functions, either superfluous or harmful to their environment. For
the sake of the body as a whole, the cells will bring this mechanism into practice
and transform themselves into a so-called self-destructive program on their own
for disposal. In this process, they will even be noble enough to set aside
their left-over machineries to put their residuals in a ‘disposal bag’ so that
no pollution to the environment will be dispersed. 6park.com
The machinery of cell apoptosis is controlled by a set of genes, probably a dozen, dozens, or maybe even hundreds
of different components, which come into a coordinated play to meet the
purpose. One or two of the critical genes in a series become mutated or somehow
lose functionality, then the whole of the mechanism will be knocked out. In
doing so, these devilish cancer cells thus win a big ‘unshackling’ victory, at
least they themselves are smarter than others, even if they know they are
useless to the body, they could now choose not to face themselves to the
miserable fate into the grave for Dutch act, or suicide, so that they could
survive and continue to grow to practice their own individual living journey. 6park.com
Next effort would, in turn, be made in dealing with another ‘curse’, the aging of the cells, SENESCENCE.
Derailment of this program is in demand for the cancer cells to proceed freely
to their course. 6park.com
Normally the body cells can split about 50 times. In order to tally how many times each cell divides, in each
division cycle the cell itself will cut a small piece of fragment of chromosome
ends. Although the gene or protein coding region rarely sit at end of the
chromosome, but its length is of vital importance to the cell to be in either
younger or elder status. The more cell division the cell makes, the shorter
terminal chromosome ends will become. When the terminal chromosome end is
chopped to some critical length, cells are no longer dividable, and thus the
aging or senescence of the cell applied. It is a trait to prevent a cell from
an unlimited split. 6park.com
Here is a problem. If this mechanism of cell aging or senescence is universally applied to all body cells without
exception, our offspring cells will be served fewer cell division cycles as
compared with that of the parent, and then all the species will ultimately be
extinct from existence after a few generations. 6park.com
Thank God, for us, the body is equipped with a reset machinery for use only in the germinal cell or maybe stem
cell. It is amazing that this mechanism will reset our germinal cell to a
time start at point 0 line. So, for our human beings and animals,
the offspring can live a similar life expectancy as the parents do. This
mechanism is used very rarely, normally only in germinal cell, to rebuild or
refill the chromosome end to the God assigned length or original ones, so that
to make the germinal cell with a new start from the very beginning. 6park.com
But somehow, with the loss of gene functions in some cancer cells, they coordinate their whole genome activities
in harmony into some degree of a little confusing so that a time of chaos is
felt by them. By some kind of weird command, they recall this rare
mechanism to render the cancer cell to this reset mechanism into play
again. And now, this cancer cells become the super ones, which have
already accumulated more than 3 important genetic changes mentioned
above. At this point the so-called cancer cells can be said to be mature,
full bloom cancer cells. Technically it is said that these cells acquire the
characteristic of REPLICATIVE IMMORTALITY, they are no longer limited by the
number of cell division and could theoretically replicate forever. 6park.com
The last two traits, or mechanisms, that the cancer cells are in need of expedited acquisition, are the ones that
are nutritional supply related, i.e. ANGIOGENESIS and INVASION and
METASTASIS. When the cells simultaneously or alternatively obtain these
two traits, cancer cells will reach the level of top malignancy. 6park.com
Cancer cells start to grow from a very small amount into an explicit size of solid tumor, maybe not more than 2
mm in size. It will be shown that some degree of shortage of local supplies is
applied just only by the diffusion of nutrients and oxygen from peripheral or
adjacent blood vessels to support the consumption of the need in central part
of the tumor mass. Like the construction of a new metropolis, both inside
and outside of the city, a new road network for the logistical communication
has to be constructed. Angiogenesis factor up -regulated following some genetic
changes promotes blood vessels to sprout into the tumor mass, and to leave the
mass with no corner or shaded area for necessary logistical exchanges. It likes
that the road-building-up to access to any part of the ‘building’ or here solid
tumors, is applied, so that every single cell in the solid tumor has no worry
about shortage of ‘water, electricity, food, and essential materials’,
otherwise the cell would stop growing when there would be a shortage of
nutritional supply. Cancer cells at this stage would witness another big
victory to have their durable colony! 6park.com
In order for more colonies, the final trait the cancer cell is in need to acquire is migration and invasion,
the technical term as metastasis. Initially, cancer cells are in a local growth
and they get familiar with the local situation and adopt to it. Generally, it
is not easy for them to migrate to another unfamiliar place to settle down.
Once they get a new set of genetic alterations, which, in turn, make them easy
to settle down into the new land. As soon as they settle down in the new
land they are going to grab more revenues and resources for their malignant
growth, like the ISIS in the real world. 6park.com
Cancer cells at this stage like a successful devilish war lord now. They are now witnessing their final win with
a big smile! If cancer cells develop to this stage, the human body has to
admit that it basically has no good way to deal with this devilish war lord
anymore. Unless some lethal genetic alteration occurs in all those cancer
cells, death of the human body would be most likely the final outcome. 6park.com
Of course, if the cancer cells were successful, they would just enjoy their successful endeavor for a short period
of time. While they destroyed their environment, they finally had to be
some heroic martyrdoms too for what they have done. However, before the cancer
cells proceed to their final destiny, they are not even going to consider this
doomed fate. They are wayward to enjoy completing their individual life
process of fun. 6park.com
To this end, we will see how the cancer cell grows into a cancer mass. It is, as a matter of the fact
indeed, not an easy thing! We take a break to our story here. 6park.com