Biology of Cancer
Biology of Cancer
Cancer is a genetic disease and it occurs by mutation or abnormal activation of cellular genes that control cellular growth during cell replication (division or mitosis). The abnormal genes causing this mutation are known as Oncogenes. As many as 100 different oncogenes exist. There is also another type of cells known as tumor suppressors or anti-oncogenes. Their role is to suppress the activation of oncogenes. In conclusion, cancer occurs when oncogenes are activated and tumor suppressors are inactivated. Despite the mentioned processes, only a minute fraction of the mutated cells in the body could lead to cancer.
Biology of Cancer / Ecosystem of the Human Body
The survival of cancerous cells depends on the environment or ecosystem of our body we have been creating for a long span of time.
First, the mutated cells have no survival capability and cannot compete with a normal cell unless there is a favorable environment for the mutated oncogenes. Second, some of those cancerous cells are destroyed by our immune system before they grow into cancer. Hence, a healthier body has a better immune system capable to destroy the unwanted cells. Third, researchers point out aging as contributing factor for cancer. Elderly with a compromised immune system are more susceptible to various infectious disease and cancer. Also, people on immunosuppressant drugs after kidney or heart transplantation are more prone to develop cancer. Fourth, cancer to develops several oncogenes must be activated. One solo mutated cell cannot cause neoplasm to occur. This simultaneous activation is needed to form blood vessels to transport nutrients to the mutated cells. Without this needed nutrition the cancerous cells will not thrive in our ecosystem and will undergo cellular death
Biology of Cancer / Cells Mitosis - Division
Mitosis is called also cells reproduction. This process happens when a cell splits to form identical daughter cells. This division happens during tissue growth or replacement.
Genetic Material -DNA
The chromosomes have ends called telomeres and those telomeres have the ability to shorten after each cell mitosis or replication. Once it reaches its growth limits it is called the Hayflick’s limit. Cancer cells exceed this limit. The telomeres continue to grow and the mutated cells become immortal – Hayflick’s limit is exceeded.
Normal Cells Division
The division is tightly controlled by signals which role is to coordinate the activities of the cell and its growth level. Normal cells division is tightly regulated. Cells are more adhesive to one another and stay in place. When new cells are formed the oldest and damaged ones undergo programmed death called apoptosis.
Excessice Cells Division
Cancer cells do not respect the cell growth limit and programmed death. There is an uncontrolled division of abnormal cells in the body. They are less adhesive to one another and when the nutrients and the environment become harsh for their existent they tend to wander through the bloodstream to other places in the body and find nutrients and survive.
Biology of Cancer / The Real Killer
Malignant tumors known also as cancers are not encapsulated formations and have the tendency to spread to other regions of the body. Whereas, localized cancer does not go beyond its primary region and it is called cancer in situ. While growing cancer needs nutrients, hence the formed neoplasm creates its own system of blood vessels (angiogenesis). The newly formed blood vessels connect to existing vessels and cancer cells migration starts via the bloodstream and lymphatic system. This wandering of cancer cells is called metastasis. Metastatic cancer goes beyond its primary location to form secondary cancer in an adjacent organ or to the lymph nodes. Places the primary tumor migrates to, depends on the type of cancer. For instance, Breast Cancer spreads beyond its primary place to the lungs, bones, and brain; Colon Cancer cells proliferate to distant organs and lymph nodes, such as lungs, liver, peritoneum (lining of the abdominal cavity); Prostate cancer could migrate to hip, spine, and pelvis bone; Lungs cancer spreads to lymph nodes, brain, bones, liver, and adrenal glands (located above the kidney); Stomach cancer goes to other locations by the mean of blood circulation to the liver, spleen, pancreas, and aorta. Cancer cells evade the immune system and cause inflammation. As a result the immune system is compromised and the body is more prone to infection. They also compete for nutrients with the normal cells. As mentioned before cancer cells multiply indefinitely and their demand for supply is tremendous. As a result, the normal cells suffer and gradually the tissues undergo nutritive death.