Hallmarks of Cancer
The
Cell Cycle
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Evading Growth Suppressors :
Cancers need to evade cellular negative regulation of proliferation. Cells ignore signals the negatively regulate growth. They
A major growth factor is EGF. EGF binds to a receptor EGFR to activate MAPK/ERK Pathways. This sends signals to genes involved in cell division and cell growth.
Resisting Cell Death:
A cancer cell that avoids regulators of cell death. Such as apoptosis. Cells undergo cellular suicide. Apoptosis occurs to get rid of cells that are no longer needed, like damaged cells which could lead to cancer
Angiogenesis:
Formation of new blood vessels, which involves differentiation of endothelial cell. Can be controlled by signals like vascular endothelial growth factor (VEGH). VEGH binds to receptors on endothelial cells. Tumors need a blood supply, meaning that tumors cannot grow or spread without it.
Enabling Replicative Immortality:
Unlimited potential for cellular proliferation. Telomeres are activated by triggers. Telomere shorten each cycle of cell division
Activation and Invasion of Metastasis:
Metastasis is when cancer spreads to a different location from where it originally started. It breaks away from the tumor and enter the bloodstream or lymphatic system. When they travel from original location, once it settles a new tumor can form.
Sustaining Proliferative Signaling:
Healthy tissues promote growth signalling pathways. This leads to the progression of cells for cell cycle. When there is a mishap this leads to uncontrolled proliferation.
Gene Mutations
Types of Mutations
The original:
ATG, AGC, TAT
Transitions: ATG, GGC,TAT
Transversion: ATG, TGC,TAT
Insertion: ATG, AAG,CTA,T
Deletion: A G A,GCT,AT
Hereditary mutations are inherited by a parent, also known as germline mutations because they occur in sperm and eggs.
Somatic mutations occur are Only present in certain cells and at some point mutations randomly occur during someone's life. They are mainly triggered by environmental factors like UV radiation.
Tumor Suppressor Genes
&
Oncogenes
Tumor suppressor genes are growth inhibitors, preventing tumor formation. When a mutation occurs it can have out of control growth leading to cancer.
p53
codes for a protein that regulates cell cycle. The role is keeping stability by preventing mutations. Plays a major role in cell cycle and apoptosis. If damage occurs this could lead to lead to cancer because of cell proliferation.
Pronto-oncogene Oncogene
code for proteins that help regulate cell growth and differentiation.
mutation of the proto-oncogene, by changing the arrangement of genes in the chromosome that moves them to a different location, or by an increase in the number of copies of the normal proto-oncogene
Altered versions of proto-oncogenes. It's a growth inducer. Can form tumors. These genes that are flipped to be on constantly.
Apoptosis
Apoptosis is cell suicide, referred to as programmed cell death. If cells are no longer needed, they will commit suicide when intracellular death is activated.
Extrinsic Pathway
(External stimuli)
This pathway is triggered by an external stimulus. It's initiated by the binding of death ligands to their transmembrane receptor, Receptor Mediated programmed cell death.
The cytokine is an external stimulus. Tumor necrosis factor is a cytokine that induces this pathway. TNF induces cell death cancerous cells. Conditions that trigger TNF are exposure to radiation, viral toxins, and elevated temperatures.
Intrinsic Pathways
(Internal Stimuli)
Plays a role in apoptotic response to anti-cancer drugs. It is inside of the target cell There is an organelle that plays a role in executing this pathway apoptosis, it is the Mitochondria. It is known as the Mitochondria-mediated death pathway.The stimuli include hypoxia, genetic damage, and oxidative stress caused by free radicals.
It is promoted by Bcl-2 proteins, have one or more BH domains. It is overexpressed in cancer cells because of translocation. It imitates as if it is an oncogene by promoting survival of cancer cells that would have normally died because of apoptosis.
Can diet play a role in cancer development and prevention ?
According to research, some foods like red and processed meat, and salt-preserved foods could increase the chances of someone developing cancer. on the other hand, fruits, and vegetables can reduce the chances of getting cancer.
Fruit and vegetables have a source of many vitamins and minerals. There is evidence proving that red meat and processed foods can increase the chances of stomach and pancreatic cancer. in some of these foods, there are chemicals such as nitrate which is used to preserve the meat. Grilling can also increase the chances because of the carcinogen Polycyclic Aromatic Hydrocarbons (PAH) and Heterocyclic Amines. These carcinogens are produced when cooking meat. For example, the burnt part of the meat is what is considered cancerous.
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How can chronic inflammation and infectious agents can lead to cancer ?
Chronic inflammation can increase a person’s chance of getting cancer. Cancers that are caused by infectious agents, such as Helicobacter pylori.
H. pylori is a spiral-shaped bacteria that cause infections in the stomach which eventually can lead to cancer. This bacteria enters the digestive tract that can leads to ulcers in the lining of the stomach.
