Hallmarks of Cancer: Assignment

Running head: HALLMARKS OF CANCER
HALLMARKS OF CANCER
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HALLMARKS OF CANCER
Figure1: is a simple diagram of the 10 hallmarks
of cancer.
Cancer is a disease that is typically
associated with abnormal cell growth;
cancerous cells have the potential to
metastasise. The development of tumours
can be associated to the 10 hallmarks of
cancer (figure1). The 10 hallmarks of
cancer are evading growth suppressors,
avoiding immune destruction, enabling
replicative immortality, tumour-promoting
inflammation, activating invasion and
metastasis, inducing angiogenesis, genome instability and mutation, resisting cell death,
deregulating cellular energetic and sustaining proliferative signalling (figure1) (1).These
hallmarks all influence the aggressiveness of the cancer thus highly influencing the course of
treatment suggested for specific cancer types. A common treatment for cancer types is
chemotherapy; chemotherapy entails the use of various drugs that target these hallmarks.
One of the hallmarks of cancer is the sustained proliferative signaling. It mainly helps in
answering the questions like how cancer cells gather the ability to undergo replication at a
continuous rate. Cancer cells are mainly seen to continue replication due to sustained
proliferative signaling. Normal tissues are mainly seen to control the steps of production and
releases of the different growth promoting signals. These signals help in instructing entry and
progression of the cells through cell growth and different division cycles (1). They help in
maintaining homeostasis of cell number. Thereby, they help in maintenance of normal
architecture and function of tissues. Cancers mainly are different as they acquire the capability to

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HALLMARKS OF CANCER
sustain proliferative signaling by mainly increasing the production of growth factor ligands.
There is also signaling of nearby normal cells that helps in providing a supply of growth factors.
It also helps in increasing their levels of receptor proteins. Besides, there are also additional
effects that result in contribution to the different types of proliferative capacity. Activation of the
downstream pathways by mutation mainly (B-Raf, PI3K) and hyperactivity of PI3K helps in
abnormal proliferation (2) (Figure 2). There is also deregulation of negative feedbacks that are
mainly seen to dampen the abnormal proliferation.
Figure 2: Hyperactivity of PI3K helps in abnormal proliferation of cancer cells
Source: (2)
It is found that in addition to the different stimulating growth signals that helps in cancer
progressions; there is also a need for evasion of the different cellular negative regulation of
proliferation. This acts as a cumulative factor that supports the excessive growth of the cancer
cells. Under the different cellular abnormal conditions, tumor suppressor proteins and factors are

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HALLMARKS OF CANCER
present which are responsible for limiting cell growth (3). Two of the widely researched tumor
suppressors are RB and TP53 that acts abnormally failing to suppress the growth of the cancer
cells. The Rb protein helps in integration of signals from a diverse field of different intracellular
as well as extracellular sources. In return, it decides whether a cell should or should not proceed
through its growth and division cycle. . Therefore when RB pathway gets defective, it is seen to
promote persistent cell proliferation. When cellular subsystems are found to be to too damaged,
then Tp53 induces programmed cell death through apoptosis. This leads to a halt of cell
proliferation when conditions become abnormal. Here, cells are seen to “talk” with each other
that help in a procedure called contact inhibition. A defective TGF-b pathway is seen to promote
malignancy as it cannot takes place in apoptosis in abnormal situations and cells continue to
grow (4). Cancer cells have the power of evading TGF-b anti-proliferative effects that adds to the
situation (16).
Another hallmark of cancer is avoiding immune destruction by the cancer cells. The
human immune system has the responsibility of protecting the body faint pathogens and diseases.
It also plays an important role in clearing the unhealthy and ailing cells of the body. Moreover, it
also has the capability of recognizing the cancer cells and eliminates them accordingly. In the
presence of cancer cells, the body cannot provide immunity to the system (5). The cancer cells
easily avoid the immune destruction activities.
Another hallmark of cancer is enabling of replicative immortality. In case of normal cells,
it is seen that cells are able to pass through only particular number of cell division cycles. This is
called the replication potential. In normal cells, replication potential is limited mainly because of
the presence of the either senescence or crisis with the crisis mainly ending the life of a cell.
Cells usually undergo a number of cell division and then they remain alive without undergoing